Zel's Eclectic Fleet Blog (Volvo, Rover, Trabant, Invacar & Occasional Distractions)

[Zelandeth]

Finally got hold of the last couple of bits I'd been waiting on to allow me to proceed with the brake system upgrade on the Invacar.



Metric unions are needed because the master cylinder is metric, and the T is a replacement so I can replace the 4-way one the brake light switch is currently fitted to - which of course needed to be Imperial because the brake light switch is!

The switch was removed from the car and stored safely in the bag with the union it will be living in from now on while I removed the old T piece.



That's now been loosely refitted to the stud the T-piece lives on.

This has then allowed me to have a think about how I'll be routing the lines, shouldn't require too much plumbing. The line to the rear will be getting extended the couple of inches needed to reach the cylinder. I did think about remaking the whole line to avoid the need for a join...but the run is a single piece all the way to the T at the rear axle and routing it would require me to remove the fuel tank. It's getting extended!

Shouldn't take long to get things in here hooked up.



Just ran out of time today.

The mud guard will need a bit of careful attention, but even a couple of minutes has got it looking far closer to the correct shape again.





That was mostly achieved simply by standing on it! Shouldn't be too hard to save it.

I do alternatively have a couple of sheets of metal here I could probably fabricate a replacement out of if it came to that.

[Zelandeth]

Now we're getting somewhere.



Front circuit is bled through, rear will have to wait till tomorrow. Everything seems fluid tight though, though everything will be given a bit of a tighten once it's sat overnight anyway.

Brake light switch is back in place. I'd have rather had it flipped through 90 degrees to make clearing the master cylinder bracket and speedometer cable less of a hassle. However the switch is just too bulky for that and would foul on the bulkhead.



Have encountered one slight snag though. I may need to source a longer pushrod for the master cylinder.

I didn't notice when I swapped it over that the new cylinder has the resting position further forward than the original one. Oops.



This results in the handlebars sitting depressed a couple of inches even when the brakes are fully released.



There is some adjustment available in the pushrod, but probably not enough. One possibility is that I *may* be able to drill an additional hole in the yoke. There are already three or four for different braking systems so one more won't be a problem. Will probably mean taking the whole handlebar assembly apart to gain access though. Won't that be fun...

Hoping this won't be too much of a headache to resolve. Ah, the joys of trying new things out.

[Zelandeth]

Few steps forward today.

Had a closer look to see how far out we were on the pushrod clearance issue. Not very much is the answer. This also really highlights the mechanical advantage in the handlebar setup. This equates to a little over 3" of travel at the bars.



With the adjuster backed as far off as I can without worrying about the nut backing off and coming loose (which would be bad), I was able to reduce the offset to this. The thing I've circled is the little rubber stop the handlebars usually rest on.



For reference, here's the same clearance at the same spot yesterday.



The loss of that bit of travel probably isn't the end of the world (keep in mind this cylinder has a slightly larger bore, so will require slightly less travel but be heavier to operate). That's plan C at this point. I don't like the fact that the return spring tension on the 'bars is resting on the pushrod, as that means any failure of the adjuster locknut or the pushrod retaining circlip on the master cylinder will result in the pushrod ejecting itself from the braking mechanism. This Would Be Bad.

Plan A is to pull the yoke out and drill a new pivot hole slightly above and forward of the existing one. Couple of reasons I prefer this.

[] Firstly is that it removes the aforementioned situation where it's not entirely beyond the realms of possibility that the master cylinder could spontaneously disassemble itself at 70mph on the sliproad coming off the A5. The resting position of the handlebars will keep everything under (light) compression. If the adjuster backs itself off you'll notice the brakes feeling sloppy and hear it rattling long before anything comes apart.

[] Secondly, shifting the pivot point slightly higher thanks to the geometry of the linkage will increase the mechanical advantage provided, so make the brakes lighter - providing an offset for the slightly larger bore cylinder. I'll be taking some careful measurements beforehand to make sure I've still got enough clearance to get a full usable stroke and that the pushrod isn't going to get pushed at too much of an angle. Stroke measurement is something I need to be particularly careful of too given that my knees are closer to the bars than in a standard car due to the upgraded seat. No, there's no way in hell I'm changing that back...I like being comfy!

I'm going to do some testing with the setup as it is now though. Given that this is all very experimental it's entirely possible that I'll find that this cylinder just doesn't work...I wind up with impossibly grabby brakes, or it's like trying to brake a 1920s bus with cable brakes because they're so heavy. Might need to mess around with an adjustable bias valve to prevent the front wheel locking up...I just don't know at this point. I'd rather know the system is fundamentally sound before I go modifying things permanently. Plus I know that getting the handlebars out is going to be an absolute pig of a job.

I did look at removing the handlebars quite early in the restoration as it would have made cleaning them up and painting them massively easier. However they're (as you'd expect) very solidly mounted by a load of fasteners. All of which are to put it politely, disinclined to acquiesce to my request that they move. At least I am armed with a decent selection of Imperial tools now at least so I'm more likely to get there in the end. Plus one of the worst fasteners is on the ball joint, and that's about to be replaced anyway.

I'm half tempted to get the whole thing powder coated while it's off the car. It's such a visually striking bit of the interior that it would really help tidy it up I think. Not sure...either way it'll definitely get some better paint while off the car. Would be sticking with black, pretty sure that's what it was originally painted.

Got most of the system bled through this evening before running into a snag. The offside rear bleed nipple is thoroughly seized. I cheated when originally setting this up by filling the cylinder by hand, fitting it and then bleeding from the pipe union. However that union is also a little chewed up (the run between that cylinder and the axle flexible line is one that came on the car as it's spotless cupronickel), and rounded off the moment I touched it today. If I apply any more force to the bleep nipple it's going to either snap off or strip. I very much doubt it will crack off.

Fair enough. I'd pondered replacing the wheel cylinders since day one. I was frankly astonished they were serviceable given the age and conditions they'd been stored in. They're not expensive, so I think it's time to change them. The nearside one needs to be removed from the hub at some point to replace the rubber boot around the handbrake linkage as it's perished and torn anyway. So time to get three new cylinders in and just change them I think. That way the only ancient bits of the brakes left will be the drums, a few springs and the shoes. All good things from the perspective of long term reliability. I'd like to take the opportunity to dismantle, clean and grease the adjusters too. I didn't really know how they worked when I first got the car back on the road, but now I have that knowledge I'd like to do some preventative maintenance there. If I've got braking work to be done, may as well do the lot.

When I was first reviving the car I didn't really know whether it would be sticking around long term and whether it would be an occasional weekend toy to take to shows or actually see regular use. So there were a few instances of reusing older parts and semi-temporary bodges that I knew I'd likely end up revisiting at some point. As I've found I actually really enjoy driving the car now it's obvious to me now that it's well worth sorting those things out now once and for all.

On that list is also sorting out the metalwork in the engine bay. While the actually important bits of tin that route the cooling air are okay, the splash guard is in a right state. Not likely to find that sitting around anywhere so I'll probably need to make something up myself. That's one I've been putting off though as it's probably going to be an engine-out job because of how the shields are fitted. On the plus side, at least they're not critical to engine cooling like in a VW. The "snorkel" on the engine cover itself serves that purpose instead, ensuring that cooling air is drawn from outside to minimise the recirculation of warm air. I do still plan to fit a temperature gauge though...not having one just bothers me! Thanks to whoever suggested one of the types popular among the air cooled VW crowd that just clamps to a head under the spark plug, that's a way more elegant solution than a wet oil temperature sender that I was originally planning to use.

That's a way down the list yet though!

Even with there still being a bit of air in the brakes though I do have something of a pedal, albeit a very spongey one. Just pushing the car back and forth in the garage it feels like they're working properly and we've got braking from both ends. Doesn't mean much, but from a purely psychological standpoint it was nice to see!

On another forum someone had mentioned that it looked like there was a worrying lack of clearance between the front wheel and the brake master cylinder. They're right, in a lot of photos it does look quite close. That's more down to a bit of an optical illusion though just how things line up. Trying to get a photo from a lower angle (tricky with the body in the way!) shows there's a decent gap.





Really shouldn't be any worries of these making contact. Especially given how little weight there is on the front, even under heavy braking the nose doesn't dive much. Glad they asked the question though as it's the sort of thing which could well have been an issue with the new cylinder being so much longer. Glad they promoted me to check.

[Zelandeth]

Nothing actually done on the Invacar today, though yesterday evening a pair of wheel brake cylinders were ordered.



Went with the same supplier that I got the brake hoses from as their service was so good last time.

Also on the subject of buying things I'm keeping tabs on this, hoping it doesn't go for silly money.



Cylinder head temperature gauge. One of the three instruments which I'll have in the little pod under the dash. Other two will be a voltmeter and a clock. The lack of the latter I've found really irritating - though it will require routing of a dedicated battery feed which is a little annoying given it's basically the furthest point in the car from the battery more or less.

[Zelandeth]

Today's adventures start on the electronics workbench.

Our patient was a lovely little Prinztronic Mini7 calculator I picked up about a week ago.



While it powered on there was no response from the keypad (aside from the number 2) and there was clearly an intermittent issue with the power supply.

This isn't a particularly high end calculator...in fact it's very much built down to a price. No screws on the case, it all just clips together.

It is quite stylish though (especially in this two tone blue) and by the standards of the time was fairly compact. Though I'd probably have cursed the dependence on AAA batteries with no DC input jack back in the 1970s...

Took a while to figure out how to get it apart without damaging anything but wasn't that hard really.



No surprises to find a TI TMS series chip at the heart of a calculator from this era - that era being pinned down to mid 1975 thanks to this date code.



There is one other IC in here which I'm pretty sure is just a display driver given where it is in circuit.



Don't recognise that maker's logo. Anyone able to ID it?

The reason for the intermittent power was a dead simple cracked solder joint between a battery post and the PCB.



Easy repair.

The issue with the keypad became self explanatory the moment I started to dismantle it as the metal domes from the keypad switches started to cascade over the desk like metallic confetti.



Those domes should all be stuck to this PCB!



Getting these all back where they were supposed to be was a bit like trying to herd a scurry of squirrels who are all hyped up on Red Bull, but we got there in the end.



I was quite interested to see how the keypad legends were printed...I had assumed the legends were screen printed on the back of the keys themselves. Was quite surprised to find that it was actually just a printed sheet of paper behind the keypad. There are little lenses moulded into the back of the keys which makes the printed text look a little larger.



Quite clever actually. Means they only needed to make one standard type of keycaps for the whole range, just printing a bit of paper to accommodate different layouts or features.

Plus it looks really classy I reckon.



That alone was responsible for my deciding I needed one from this family in the collection the moment I saw one.

Glad to report that it now seems to be fully functional again. I do need to replace the decomposed foam behind the battery contacts, but that's a job for another day. For testing purposes this is absolutely fine.

It is a comically slow calculator though for the period...square root calculations take the best part of 1/2 a second. Division about 1/4 a second...which by 1975 is quite slow. It also doesn't have any logic to stop you taking the square root of negative numbers. It does correctly catch divide by zero though.



The small u at the far left is the arithmetic error indicator on this display.

Should be able to get a page put together for it on the website soon hopefully.


We were then able to move into the garage.

Knowing I was going to need access to the rear brake unions on the flexible lines I needed to remove the rear service hatch again, so decided it was a good opportunity to test something out.

The flashband I'd stuck to it as sound deadening did help, but I don't think it made nearly enough difference to be worth the weight. It pretty much doubled the weight of the hatch. It also added enough extra to the dimensions to make it even more awkward to remove. Additional mechanical noise was being added as well as the insulation never really adhered well to the underside so it was usually sitting directly on the CVT pulley cage.

So today I pulled off most of it (a few areas were thoroughly stuck and weren't going to come off without a huge fight) and gave it a few coats of rubberised truck bed liner.





Several more will be added next time we get a break in the weather. It's already noticeably dulled down the sound of you tap it so mission accomplished hopefully. I'll report back on whether I notice any difference when driving.

The main mission for the day was getting these fitted.



Delivery was once again ridiculously quick from MEV Spares. Ordered at 23:55 on Thursday, parts dropped into my letter box before midday on Saturday.

Nothing particularly complicated here, just fiddly.

I knew I couldn't easily get the union on the back of the cylinder off so didn't even bother. Just pulled it at the Flexi end and planned on feeding the whole lot out through the backing plate in one piece.

Went pretty smoothly. Getting those U clips off the back of the cylinder is a heck of a lot easier when you know how they work! I must have wasted hours on it when I took the first wheel cylinder off KPL, this took me about ten minutes.



Before going any further I made a point of double checking what the threads in the wheel cylinders were *before* I had flared the new brake line... I'd already been very nearly caught out when the master cylinder turned out to be metric. These aren't.



Once I'd suitably plugged the brake line off the old cylinder so it could spray brake fluid into my eye, I was then able to use it to give me an idea how much pipe I needed.



Also checked very carefully to ensure they were indeed as close to identical as possible.



All indications were good.

It was at this stage I ran into a slight snag. These new cylinders are much more of a snug fit through the slot in the back plate. This wouldn't be a problem with the hub on most cars where you can slide it in straight...however thanks to the rather bulky hub on the Invacar you have to slot it in at a slight angle to clear the wheel mounting flange. Just enough to make it bind up. After a bit of head scratching I eventually chose to very gently tap it past the tightest point with a hammer and block of wood. Hopefully nothing was harmed...but short of removing the whole hub I couldn't see an alternative.

I then had a mental foul up and convinced myself I'd fitted it upside-down and spent 20 minutes pulling the cylinder out again to compare to the original. Of course it was absolutely fine so I had to put it all together again.

By this point it was getting dark...and right about the point it got properly dark, my work light decided that this was an ideal opportunity to run out of charge.

Cylinder is in, horseshoe clips are both in, hydraulic line is connected at both ends and the rubber boot is correctly seated around the cylinder and handbrake linkage.



The original pipe had been touching the suspension arm at the lower corner so I deliberately made the new pipe a bit longer so it could be routed better. May see about adding a clip roughly level with the shock absorber to ensure the new pipe can't vibrate.

I really do need to get a wire brush and some paint on that rear suspension at some point, it just looks horrendous.

Sadly thanks to having run out of daylight (it started raining while I was tidying up too), I've a few things left to fit...



No way I was trying to refit those springs in the dark. They're fiddly enough in full daylight, trying to fit them in the dark is just asking to get a spring in the eye!

Hopefully get this side finished and the other one done tomorrow. At least the nearside one I can get to with the car in the garage, offside one requires me to wheel it outside first.

[suffolkpete]

There is one other IC in here which I'm pretty sure is just a display driver given where it is in circuit.



Don't recognise that maker's logo. Anyone able to ID it?

Is it National Semiconductor?

[Zelandeth]

There is one other IC in here which I'm pretty sure is just a display driver given where it is in circuit.



Don't recognise that maker's logo. Anyone able to ID it?

Is it National Semiconductor?

Correct. Had a couple of folks let me know what it was now. I really ought to look up and save a cheat sheet for things like this to be honest!

[Zelandeth]

Today the weather was *perfect* for crawling around on the ground messing around with brakes!



Before I started to reassemble the offside brake I wanted to address the fact that the shoes were really quite badly glazed.



To address this I made sure everything was wet, working upwind, and while wearing a mask gave them a bit of a scrub up.



Not perfect but a whole lot better. I really should just treat it to a full set of new brakes shoes to be fair, the ones on there came from one of the many boxes of random spares I got with KPL.

Built the brake assembly back up...



You can see there how much the wide hub really gets in the way.

Got the free play adjusted...



The system bled...



Then a quick walking pace test done in the garage. I couldn't start the engine as I'd end up asphyxiating Chris who was working in the room that backs onto the garage, but it was enough to give us a bit of a test to see how things were behaving.

YouTube Link

Still too much free play - but I've not touched the nearside or front brakes yet, and given how useless the handbrake had become I'm certain that the nearside at the very least needs adjusting. It's immediately obvious though that when you "stamp" on the pedal that the response is a lot more positive now. The brakes before always felt quite wooden. Will be curious to see how things are once they've all been done.

The nearside wheel cylinder WILL be getting replaced, it's just going to get done at some point when it's not -2C outside. The offside one was replaced because I couldn't bleed it, the nearside one is actually working just fine and is basically being changed as a bit of future proofing. It can wait for warmer weather!

Last job for the day was to see if I could do something with the front mud guard, which as can be seen a few posts back was thoroughly mangled. Fifteen minutes bashing it with a 4lb lump hammer against a tree stump later we had this.



Which while still not pretty, will be absolutely fine once it's painted up and buried under the front body moulding.



That paint will dry to a satin hammered finish which should help hide a lot of the imperfections.

I'm not bothering to repair the original mounting point. It's an annoying, fiddly arrangement which basically requires removal of the brake master cylinder to get the guard off...So instead I'm going to fit a couple of 90 degree brackets to it and run a couple of bolts through the bulkhead.

Hopefully get the rest of the brakes cleaned up and adjusted tomorrow.

[Zelandeth]

As expected the nearside brake shoes were quite glazed so were given a scrub up just as the ones on the other side were. My prediction that the adjustment was "drastically in need of attention" was also correct. I think I got a full three turns on it before we got to the point where the shoes came anywhere close to touching the drum. Beyond that it was just a case of "reassemble like yesterday" and to tweak the adjustment of the offside one so they felt even.

This has vastly improved things, there's far less dead travel in the brakes now - though it's still closer to my knees than I'd like because of the essentially lost travel as the bars are starting slightly depressed.

The paint on the mudguard has dried up pretty much as I'd hoped.





Once it's in place I think it will be perfectly presentable in the context of the overall appearance of the car.



I have now attached a bracket to it (but totally forgot to take a photo of it), so should be able to get it refitted soon. I'm probably going to leave that be until I'm finished all the work up front as it gives me a bit more room to work having it out of the way.

I think the plan for next time I'm in the garage is to see if I can get the handlebars detached to experiment with drilling a new pivot point to attach the brake cylinder clevis pin to. See if I can get back that bit of lost motion. *Hoping* that won't be too massive a mission.

To do list before the road test I think:

[] Modify brake lever pivot point to suit new master cylinder.

[] Replace the furthest forward ball joint. I've identified that's where most of the play is - you can hear and feel it going "clonk" when you shake the drag link.

[] Fit foam padding around the top fuel tank strap.

[] Refit front mud guard.

Then I think we'll be good to go.

-- -- --

EDIT:

The webpage for the Prinztronic Mini 7 Calculator is now live over on my website.



Quite a striking looking thing I reckon.

[Zelandeth]

Noted today that the handlebars in TPA are sitting correctly on the brake stop now. I'll need to investigate tomorrow to see what's moved or settled. There's still more travel in the brakes than I'd like - though I think I need to clear the drive so I can actually test it under engine power as the feel is completely different. There used to be a certain amount of dead travel then a very firm point where all the braking effort was done in virtually no actual travel - whereas it feels far more progressive now. Proper testing needed.

Another parcel arrived for TPA this morning which contained this.



Probably paid a bit over the odds for it as they're sought after by the air-cooled VW crowd, but to be honest I was willing to pay a few quid extra for a halfway decent instrument that doesn't look totally out of place anyway. This is a thermocouple type which saves me a bit of wiring and came with the sender too, whereas most of the modern automotive ones use a conventional thermistor and require a 12V feed.

The sender was looking a little sorry for itself though.



Nothing a few minutes and some heat shrink tubing couldn't sort though.



A quick bench test showed that both the sender and the gauge itself both seem to work just fine. A bit of a relief given how sensitive the gauge movement must be...sure far too many of these have been zapped over the years by being connected to 12V.



Fitting the sender is a dead easy procedure here as the ring terminal simply clamps down under the spark plug. It seemed the obvious choice to me to put it on the nearside cylinder as that's the one which is shaded by the oil cooler so in theory should always run the warmest (same reason that cylinder number 3 is always the most likely one to overheat on air cooled VWs). With it in place I ran the engine for a few minutes to make sure I was getting a reading. All seems good.



I *know* how thermocouples work...but there's still something somewhat magical about seeing something electrical working purely because you're making something hot.

Unfortunately I can't fully wire it in just now as I don't have enough wire in stock. Have got some on order. The gauge has been loosely fitted where it will live though. Doesn't it look so much better than the mid 2000s Cheap 'n' Nasty (TM) gauges that it's currently sitting next to?



The matte finish to the glass is an immediately obvious advantage...the others generally have done a great job of reflecting the sky from above my right shoulder. I'll be replacing the other two with something a bit more period appropriate shortly.

I think it's fair to say that TPA does have a bit of an issue with leaky valve stem oil seals. She's absolutely fine if used regularly, but the first startup after sitting for more than a few days usually results in quite an impressive smoke screen.



Honestly not worried about it though as I've never noticed anything while driving and she doesn't use a drop of engine oil between services going by the dipstick. Just filed under "note and monitor" for the foreseeable future unless it gets massively worse.

Having satisfied myself that the rear brake circuit is fluid-tight I buttoned back up the service hatch - finally got around to swapping out the 8mm nuts for wing nuts so I don't need tools to open it up any more.



Yes, where possible I did go back and line them up with the edge of the hatch outline to satisfy my OCD.

It's a tiny thing, but should save me a couple of minute every time I start or finish a CVT servicing session.

Last job was to try to change one of the ball joints. Decided to go for the one on the handlebars as it's by far the easiest to get to, despite it being one that didn't have any obvious issues.

Getting the locknut free did require a good belt from the big hammer but somewhat to my surprise everything came apart without much fuss at all. One good whack on the spindle and it was free. Didn't even need to break out the ball joint splitter.



Comparing the new and old ones shows the newer one to have a far longer tapered section...though I'm not sure if this might be to some extent the manufacturer trying to get away with using one part for a few different applications. Shouldn't be a problem at all in this case, will just mean that the body of the joint will sit a little lower. The actual size and profile of the taper at the narrow end is exactly the same as on the old joint.



The only headache was the seemingly inevitable moment when the spindle started to rotate while trying to tighten up the nyloc nut. Pair of pliers were able to provide enough friction though to get things tightened up. Job done!





Here are the markings from the original one in case they're useful to anyone.







To be honest with a new clip for the boot and some fresh grease this one could probably do further service. I originally thought the rubber was perished, though that turns out to just be the paint and gunk stuck to the outside of it - though when they're so cheap you do have to wonder if it's worth servicing one rather than just replacing it! It can go into the box of serviceable spares though in case I have one that disintegrates at short notice or something.

Not too bad for an hour and a bit. Also gave the interior a hoover out and cleared out the plethora of tools which had built up in the cabin.

This evening I had a bit of a reorganise - which involved removing basically every single thing from the shelf above my workstation. The reason was simple...I'm sick of not being able to listen to music properly! The room where the best audio setup in the house lives is currently being occupied by someone working from home...so I've been unable to use it since this time last year. My little Bose Wave does a cracking job at filling the room at normal listening levels...but it has its limits. Sometimes I like to just lose myself in music a bit, and for me at least part of that is feeling a fair amount of the music as well as hearing it when you've cranked it up a bit...and the little Bose just can't cut it there.

These can though...



These are the smaller brothers to the big suckers downstairs which can just about knock the wind out of your lungs when Spotify helpfully decides to kick the volume up to 100% the moment you click play (a bug which they *seem* to have finally fixed).



The brackets holding that shelf up by the way are screwed directly into the wall studs aside from the first from the left - so there's no worry about load capacity there. Think I've actually taken more weight OFF than I added this evening.

Driving the show is the world's most scruffy Sony LBT-LX5.



I have no idea *what* the previous owner did to this poor stereo system, but it is absolutely ruined from a cosmetic perspective - to the extent that I have actually considered dismantling it to repaint the facia. However I know that I have the big brother of this system (the LBT-LX9 AV - which is what the speakers downstairs came from) in absolutely immaculate condition waiting for collection next time I'm up in Aberdeenshire...so it seems a bit pointless as this will probably get retired to the garage then. Just a shame it's visually such a state as it's absolutely fine from a functional perspective...and it works very, very well. My ability to rattle the windows has been restored.

Given the amount of things in this room that are precariously stacked this may prove to be a bad thing!