Power Brake Problem

Trigger_Andy · Post by **Trigger_Andy** » Tue Apr 25, 06 11:22 am

I cant remember if I have posted about this problem before?

OK, since I fitted my header's I have had no brakes at all. To fit the header's I had to move the master cylinder outta the way.
I should have paid more attention to what I was doing because I think I may have lost a seal. If my memmory serves me right it was a foam based seal that disintegrated what it was desterbed? The seal went between a white plastic bit and a metal spacer that goes between the master cylinder and the brake booster. I can post pictures if required.

Does anyone know if you can get spares or know of a suitable alternitive?

latil · Post by **latil** » Wed Apr 26, 06 7:31 am

I think that is just a gasket to keep dust etc out of the joint.I made a new one from laminate floor underlay which appeared to be the same foam.

Matt · Post by **Matt** » Wed Apr 26, 06 8:02 am

I don't think the item you're talking about is a seal - it's a little foam air filter which is sandwiched in the upper part between the white plastic clip-on plate and the cast metal plate . Both plates fit between the booster and the master cylinder. As far as I can gather, this vents the side of the booster that faces the master cylinder. I just use a small piece of open-cell foam cut to fit.

Trigger_Andy · Post by **Trigger_Andy** » Wed Apr 26, 06 9:15 am

Thanks for the responce.

OK Steve, I tried to suck on the vacuum hose and it dident hold vacuum. I could suck but with effort

.

I looked ansd felt inside the output rod side of the booster and could not find and tear's/holes in the rubber seal. The seal face for the Snandwich plate is in tact too. Should I be checking for a posable leak path?

Matt · Post by **Matt** » Wed Apr 26, 06 9:21 am

what do you mean ' no brakes' ?

does the pedal not move , or does it go to the floor ?

Trigger_Andy · Post by **Trigger_Andy** » Wed Apr 26, 06 9:25 am

Hi Matt,
I get a very short burst of brake effort then no force at all. I still have a solid pedal and have to push like mad to get a fraction of the brake effort I had before. Basicly I have to trundle to junction's.

And this is all since I moved it in various stages to get my headers's in.

Matt · Post by **Matt** » Fri Apr 28, 06 9:47 am

Steve - good point , but , (going from memory here , feel free to argue) the construction of this part of the assembly is such that it is absolutely not meant to be airtight .

The cast plate behind the master cylinder seals the rim of the booster's internal rubber seal to the booster body - this is where the airtight seal is - there's quite a few raised ribs on it to ensure a good seal. however , I don't think the section of the booster from which the pushrod emerges is subject to vacuum. Hence the need to vent from between the cast plate and the master cylinder as the internal volume of this part of the booster will change with pedal travel.

I'm not actually looking at the manual or a booster here, and could be talking real rubbish - could someone who actually knows put me straight if I am ?

Matt · Post by **Matt** » Fri Apr 28, 06 11:08 am

Andy - sounds like you've got vacuum initially , but it's disappearing once you've pressed the pedal .
First thing to check is that the vac hose from the carb/intake manifold to the booster isn't kinked or hasn't collapsed internally . (Had a perfectly good looking one collapse internally once - exactly the symptoms you describe) . Is the check valve where the hose meets the booster working OK?

Otherwise you could have an internal booster problem?

Trigger_Andy · Post by **Trigger_Andy** » Fri Apr 28, 06 6:57 pm

Thanks for all the reply's guy's. Food for thought.

I will have to look into a few of the points that have been brought up when I get home. Like I said before I can suck through the Vacuum line from the inlet manifold but it takes some effort. I have had a good feel inside the rubber element and cant find any tears or nicks, though it was very grubby and rusty. there's a circular rubber piece with triangle shaped metal wedges that fit inside the booster and the output rod sits inside of it, one of these wedges are missing. But it was like that before so I guess its of no importance. Is there anywhere I can buy a manual that will cover this?

Trigger_Andy · Post by **Trigger_Andy** » Sun Apr 30, 06 12:17 pm

I have found a company that sell's remanufactured Booster's on the net. Not bad at $130 each. If I fail to find/fix my problem this look's like the next step.

javascript:ol('http://replacement.car-stuff.com/parts/ ... part=Brake Booster&returnurl=null&dp=true&showdc=true#top');

Unless anyone know's anyone who sell's repair kit's?

Anonymous · Post by **Anonymous** » Mon May 01, 06 1:55 pm

Whatever you do Andy don't bodge it as suddenly being without power brakes wouldn't be nice..... just ask Wildman who very nearly took out a petrol station cos he couldn't stop.

Harmless Bodge and brakes do not mix

If you get stuck for a booster I can do one

Trigger_Andy · Post by **Trigger_Andy** » Mon May 01, 06 6:28 pm

Cheer's Will, PM me with a price when you have time.