Reactionary linkage seizing

[Keith Webb]

I have experienced a problem with the brakes on the FGT (which is fitted with the booster) where the pedal which does not return when it is released.

At first I thought there may be a problem with the booster, but releasing that made no difference. Having a closer look underneath, it seems the reactionary linkage(part 2514 in the exploded view) has become very tight on the shaft (2482). The brake operating arm (1966) which looks like a tuning fork and is the actual part with the rod pushing into the master cylinder moves freely.

I've tried liberal application of cat piss (penetrating fluid) and working it back and forward but this is very tiresome on your own as you're constantly under the truck then into the seat to push the pedal.
I'm thinking perhaps once the volatile parts of the cat piss have evaporated to try some heat.
Anyone else experienced this? It appears to be one of the more annoying things about not using a vehicle for far too long... although I don't think I have seen this happen on any of the wrecks I've encountered through the years.

[Private_collector]

Keith, is that the more complex system of booster, with the large vacuum storage chamber, or same one as F60s?

If same as mine, I can't understand how it would get tight if thats not been a problem before. When I first read your post, I thought you meant the reac. shaft itself, because thats a little B/stard if sticking. I'll have a look at my mechanism tomorrow, but I never had problems rebuilding it. Mind you, rebuild means good clean-up and paint, as far as the linkages & arms go. Booster was another story.

[Keith Webb]

No, it's the standard one across the Ford range of CMPs fitted with brake booster. The F60H was the complex one, quite different to mine.
If need be I'll take it all off, but having had the hydraulics all resleeved I'm hoping I can do it without having to remove the master cylinder (and it's 3 awkward bolts!) and then bleeding the brake system again.

Originally Posted by Private_collector

Keith, is that the more complex system of booster, with the large vacuum storage chamber, or same one as F60s?

If same as mine, I can't understand how it would get tight if thats not been a problem before. When I first read your post, I thought you meant the reac. shaft itself, because thats a little B/stard if sticking. I'll have a look at my mechanism tomorrow, but I never had problems rebuilding it. Mind you, rebuild means good clean-up and paint, as far as the linkages & arms go. Booster was another story.

[Richard Farrant]

Hi Keith,
I am not familiar with this booster, but did wonder if you noticed the pedal being tight when you initially pushed it down? If not then it could be a vacuum valve is not releasing, I have had that happen on other boosters/servos and that will hold the pedal down until the vacuum has dissapated.

Just a thought

[Keith Webb]

I thought it may have been the booster so the first thing I did was to completely take the booster out of the equation which is a simple matter of removing the clevis pin and swinging it down out of the way, so it became just a mechanical fault with the bits the pedal actuates.

[Richard Farrant]

Thanks Keith,
it was just a thought as similar had occured with me on a Bedford, but it was the valve out of adjustment, but that required removing the booster to deal with it.

I am aware of how awkward it is to access, so not an easy task. Best of luck with it.

[hrpearce]

Keith can 2482 be removed while the system renaines bolted to the truck? It sounds like dried crud in the bush of 2514.

[Keith Webb]

Originally Posted by hrpearce

Keith can 2482 be removed while the system renaines bolted to the truck? It sounds like dried crud in the bush of 2514.

The whole assembly needs to come out - theoretically the master cylinder can remain connected but probably a lot less awkward to take it out too.