brakes applying themselves after 16v servo conversion

Right I'm still having problems with my brakes applying themselves. I've done an Audi S3 18t coversion and a 16v servo and brake cylinder conversion I've tried adjusting the bars and have even changed the cylinder incase of fault but they are still applying themselves. I re-read Qpengs 18t guide and they say to use half the 20v and half the 8v hoses and all the non return valves. In my mk1 conversion all I've done is connected the S3 vacuum hose near the inlet manifold (after the S3 non return valves) with some rubber vacuum hose from a motor shop, then connected the hose to the inlet to the 16v servo. basically I haven't used anything from the mk1 is this why my brakes are gradually applying themselves? They're fine until you've driven about a mile and then they bined if you go any further they lock.   :dontknow:      :dontknow:      :dontknow:   

Which wheel(s) are binding? A servo doesn't simply apply force on its own, even if it was 0 bar vacuum, it needs the pedal to be pressed (and any linkage) to apply force to the MC. If you've eliminated the hydraulics (ie you're confident the master cylinder is returning to its start position) then it could be rear drums overadjusted, warped drums,warped discs, misfitted pads, etc. Basically, a fitting/assembly issue on the friction side. Or a kinked brake line?

one way valve around the wrong way???

Or an overtightened (rear) wheel bearing.

can't be i didnt put any on from the mk1 and the 1's on the S3 engine i never touched, theyre under the inlet mainifold unmolested. ??????????

get a picture up of the pipes i had a similar problem with one did reently where the valve was round the wrong

more likely to be as paul suggested tho worth jacking up and checking each wheel :wink:

rpatten said

can't be i didnt put any on from the mk1 and the 1's on the S3 engine i never touched, theyre under the inlet mainifold unmolested. ??????????

The car's been off the road a significant time, things can seize up etc so you need to check everything, not just assume its okay beacuse it worked before.

how could a rear wheel bearing make the front brakes apply themselves???

rpatten said

how could a rear wheel bearing make the front brakes apply themselves???

Ok so if its front brakes binding, the rear wheel bearings have no, ummm, bearing.

Have you physically checked that the servo pushrod is returning to its at rest position consistently? Left or right or both front wheels? and no binding in the rears at all? Have you kept the diagonal split when plumbing in the brake lines to the servo?

the cars bben off the road 4 weeks but we've been pushing it in and out the reason for me thinking it being the brakes themselves not a bearing is that when the brakes are seized if you crack open on of the copper pipe conections on the cylinder you can physically hear the calipers release and the brake lights go off.
The vacume hose thing could that slowly with the engine running at high rpm apply the brakes?

Vacuum, on its own, cannot apply the brakes. I'm not sure if a servo could have a fault which means it does, but a properly working one will only push the master cylinder's shaft, if its own shaft receives a push - that's what the servo does, it amplifies the effort of the original push. The vacuum is used as an energy source, and is stored in the servo body.

both front wheels and i think the rear aswell yes i have retained the diagonal split. certainly seems to go back to its rest position.
It's wird because when your bleeding the brackes if something was sticking you'd of thought you would of noticed it then but nothing and like i say it drives great and the brakes seem fine but then you notice the car doesnt want to coast freely, you drive a little further, just normal driving and the bineding gets worse until your down to 1st gear and the engine wants to stall.
don't get it?
cars are like women stubbon money grabing head aches

New or secondhand servo?

Ill take some pictures of the pipe work and servo just incase i have ballsed it up but the bloke whos helping me is a mechanic and a bloody good one, just starting to run out of ideas

You could try disconnecting and plugging up the servo vacuum pipe, this should pretty much eliminate the servo from the system. The brakes will be hard to push and the pedal travel longer, but it will give you an opportinuty to test.

oh it's new, i didn't want to skimp on the brakes my thought was the chances of me getting a faulty new one compared to a 2nd hand braker?

yeah i'll try it but if it turns out to be that i'm gunna be narked off cuz it's a bleeder to get off now i've got even less room under the bonnet and i can't see GSF wanting to take back a servo with half the thread cut off.