no brakes

i have a 85 vw jetta, i have had the brakes changed,calipers,brake lines, rotors , master cylinder all changed.. and i still have no brakes... they wont pump up. i was told i had a bad master cylinder and so far have replaced it 3 times... am out of ideas and my mechanic cant find out whats wrong either... does anyone have any answers for me.... they have been bleed to... still nothing

Reply to
beccashady
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Find a different mechanic.

Reply to
Papa

Reply to
beccashady

Unbelievable! A brake problem should not be that difficult to solve. Do all of those mechanics work at the same facility?

Reply to
Papa

Reply to
beccashady

i presume that the pedal just goes straight to the floor, with little to no resistance.

there are 2 probible causes:

1] air in the system. pressing the pedal compresses the air giving little or no braking effort

2] fluid leak. pressing the pedal forces fluid out from the leak, so no pressure develops in the system, giving little or no braking effort.

braking systems on cars of this age are very primative (it shouldn't have abs or any other fancy gadgets) so there really is very little that can go wrong. i can't see it being a servo problem, as a defective servo would make the pedal very hard.

first thing i would do is to check for leaks. carefully examine the front calipers for any signs of fluid leakage from the bleed nipple, hose connection and around the rubber seal on the piston (might help to remove the pads). also look around the inside of the wheel for patches that look damp, which could indicate a drip.

follow all of the brake lines from end to end. check all of the joints for leaks while someone else operates the pedal. be slow and methodical, and make sure you have enough light to see what you're doing.

check the rear wheel cylinders. look arounf the hose connection and bleed nipple, then look for signs of fluid coming from the bottom of the drum. if you are aboe to, remove the drums, and pull back the rubber dust seals on the cylinders to see if they're leaking. if they are, you'll need to replace the brake shoes, as they may have been contaminated with brake fluid.

check the master cylinder for leaks. check all of the pipe connections whil someone operates the pedal. feel the operating rod that goes into the back of the master cylinder. you will be able to feel any brake fluid leak on that rod.

remember - just because a component is new it doesn't mean that it isn't faulty. occasionally dodgy parts slip thru the QC process.

if you've checked all that and there is no sign of a problem, then there is probably air stuck in the system somewhere. bleed them again very thoroughly. i'd try to bleed at least 250ml of fluid from each wheel. if you are using a method that involves pumping the pedal, do not push it all the way to the floor, this risks inverting the seals in the master cyinder.

if you've done all that and still no improvement, take it to a different vehicle technician. get reccomendations from people you. go to a proper repairshop, not a fast fit centre. explain the problem and ask them to do a full brake inspection and rolling road test (rolling road may help show up where the problem is - i.e. if there is braking effort on 3 wheels but not on the 4th, that tells you where the problem will lie)

finally - i had a similar problem after replacing all the brake lines on a '96 golf. the fault took me a few hours to find. it was a leaky pipe joint above the rear axle, where access is very tight. the leak could only be seen when the pedal was operated. it only needs a very small leak to give the fault you describe.

hope that helps, let me know how you get on :)

Reply to
Nathan Lucas

I am not a brake expert but I read a post that was similar a long while back. In that case there was a brake caliper mounted upside-down so that the bleed screw was on the bottom! This was a left caliper on the right wheel or the otherway.

Make sure all your bleed screws are on the top of the calipers.

That's all I have.

beccashady wrote:

Reply to
Mark

"beccashady" wrote

Was the master cylinder 'bench bled' or 'bench primed' before installation? (though I would think there would be signs of working if not)

I had a pinhole in one line of a mid 80s Golf in the rear. The line actually rusted through creating a tiny pin hole and no brakes. I went to a junkyard and pulled a complete brake line from a Jetta (they only charged me 5 dollars believe it or not)

I am just wondering if the power-assist brake unit - internal failure could cause complete brake failure. Hmmmm.. might be dumping fluid into the power brake unit. You may want to consider changing that. It is round like a doughnut. Also the rod from the brake pedal that has an adjuster on the end, I forget, I think it screws in and out for different pedal adjustment, hopefully that adjustment was not tampered way out or if the end can completely screw off, I forget.

Harry

Reply to
Harry

Also, like I said about bench bleeding. If the master cylinder is not bench bleed it is possible to blow the seal from repeated bleeding attempts. It is hard to tell without checking a lot of things on the car, but there is a remote possibility that you are repeatingly blowing the master cylinder seals by not bench bleeding the unit before installation. In fact, the master cylinder is void of warranty if they feel it was not bench bled before installation should say in your warranty.

However, the above is a guess from little information as it is difficult to diagnoze a problem with a car over the Internet without a lot of posts and checks.

Harry

Reply to
Harry

Anyone bother to check the slave cylinder? You really need a new mechanic.

Reply to
Joseph Meehan

I bet the dealer could fix your issue?

Reply to
Lost In Space/Woodchuck

Is the mechanism between the brake pedal and the master cylinder broken?

Aaron Hirshberg

Reply to
aaronhirshberg

Some of these VWs have brake pressure regulators. A box underneath the car that the rear brake lines come out of. Maybe they all do. Maybe yours is broken!

Aaron Hirshberg

Reply to
aaronhirshberg

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