Braking problem

[JuNK512G]

I have 8cwt van with 1300cc Ital engine & Ford front disc set up. In 2011 I fitted a new brake servo which worked fine, however I noticed last year that on releasing the brake pedal after slowing down, the brakes seemed to hang on momentarily, very very slightly. This year the same thing has happened a couple of times. This morning I drove round the block & when I used the brakes to slow down, they stayed on as if the front was locked on & actually stopped me. they remained locked so I reversed a little then they freed up. I have only done 8000 miles since fitting. I have heard there is a filter on the servo & wonder if perhaps this may need cleaning, if that is contained in the white plastic thing then it is going to be difficult to remove without taking the servo out.

[bmcecosse]

Has the 'top hat' seal definitely been removed from the master cylinder? You can test the servo by simply clamping the vacuum hose - and test if the brakes react any differently.

[JuNK512G]

Thanks for that, I'll give it a try, When I first had Marina discs, I took the top hat rubber out, with this latest set up & new master cylinder/remote reservoir, the advice at the time was to make a pinhole in the rubber which I did, I suppose that could have blocked but these symptoms only occurred every so often. Have just spoken to a friend who had a similar problem & he took the plastic arrangement thing off, inside was a small moving part which he had been advised to put rubber grease on & this cured the problem. As we are going on MOT UK soon towing, I am a little concerned & tempted to re-plumb, do away with the servo especially as It was one I bought when there was quite a bit of controversy about these aftermarket servos.

[martin418]

hi my friends mgb did the same thing and it was the servo sticking , the servo was about 2 years old , i did a bypass to prove it

[JuNK512G]

hi my friends mgb did the same thing and it was the servo sticking , the servo was about 2 years old , i did a bypass to prove it

Can you explain how you did the bypass please.

[bmcecosse]

I'm not sure a pin-hole is enough to release the fluid quickly. I assume a 'bypass' simply joins the two pipes at the servo together.

[martin418]

i used a double ended female brake pipe joiner and linked the brake pipes at the servo together ,then bleed the system as normal , and remove / blank off the vacuum pipe from the inlet manifold