Practically Classics Forum

Hi again,
I'll have a look at the various hoses and cylinders but would be surprised if they are the problem as they are all new and were working when the system was bled initially and had a pedal of sorts. I've sent an email to JL Spares of Rochdale who supplied the servo to see if they have any suggestions.
I'll report back when they reply.
John

One way valve to servo? Right way round?

P45.

If it bled initially then it would suggest a valve of some sort has locked up, when bleeding, you haven't kinked a pipe somewhere near the master cyl or servo??

Kev

Penguin45 wrote:One way valve to servo? Right way round?

P45.

If it weren't, the servo couldn't be evacuated in the first place, since the hose from the inlet manifold would be unable to overcome the shuttle at the closed end of its travel. In this case, the pedal would be hard alright, but it would move.
Also, the valve body must have a smaller stub at the manifold end than the stub that locates in the servo body.

interesting. having just replaced both front calipers and master cylinder ( rover p6) i found when parking that both front brake were locked on..pedal was firm. releasing flu in line at servo sorted it until I got home. chat with an 84 year old whom had had this car ( not mine) and others said immediately it was faulty servo. these have a spring inside that can fail or more likely a small piece of 'S---' can block a pinhole in it and cause pressure to stay in system. I didn't get to ask why to only affected front wheels?
still will be replacing servo on his say so at vast expense as its practically only thing left on system not changed. hope you get sorted.

hornchurchmale wrote: I didn't get to ask why to only affected front wheels?

Harvey would know for sure, but could it be that the servo only works on the front brakes as is the case with DAFs, some Volvos and assorted other stuff that uses this method instead of a brake limiting valve to the rear.

Nope, servo works on all the brakes, see my post in another section.

just replaced front callipers and master cylinder ( rover p6) and had experience when driving of front brakes locking on.. managed to open fluid line in front of servo and free up to drive back. didn't occur on way back..spoke to an 84 year old whom was into classic cars ( at our club meet) who said it was servo fault. seems there is a tiny pinhole that can get blocked with any debris.crap and cause brake pressure to stay on.
I fail to see why rear brakes were not affected. so new servo unit will be fitted later..( pennies in saving pot not enough at moment) do try checking servo pressure line as I did. if brake release as they ought to ..we make have small issue with crud but do also check spring in servo system is correctly fitted.seems this too can cause issues. goo luck . do update when you get sorted as it may help others.

See my post in members cars (your car) re: pressure switch before doing else

Hi all,

Just been reviewing my post and thought I should update all those who took the trouble to offer help. It's sorted now and must admit to a stupid oversight When I changed the servo I fitted the pipes from the master cylinder and that to the system I connected them what I thought was the correct way round,the pipes were of the correct length and required virtually no modification by way of bending etc.I neglected to double check the correct configuration and it turns out the 'inlet/outlet' are reversed on the replacement servo . I have now made new pipes and all is well.
Moral of the story is check,check and double check before posing a question on the forum.

Johnc