# 1990 G60 no brake pressure......WTF?????



## Corradoman8 (Sep 14, 2000)

Ok......here's what I've done:

-replaced bad master cylinder and resiviour.
-replaced rear pads/ rotors
-replace seized rear proportioning valve
-upgraded to ECS Tuning MK4 rear calipers
-bleed complete brake system.

after all that, it drove fine for two days. then coming home from work, i went to use the brakes to stop at a light and they went all the way to the floor. I ferried the car home and got it up on jack stands. I re-bleed the system and still no pressure. then upon further inspection on the ground and the ECS calipers I noticed a puddle of brake fluid. As i went back through the braking system everything was just the way it should have been except for the passenger rear caliper. It was soaked. I called ECS, and they said i had the kit to long to warrant any of it. So I forked out the $100 for a TRW rear caliper. Today I replaced the caliper and bleed the system again and STILL NO PRESSURE. 

I bleed the system in the order that the Bentley states. The new caliper isn't leaking like the old one. the resiviour is full and the level hasn't changed at all. what am I missing?


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## germancarnut51 (Mar 23, 2008)

First of all, don't throw away the leaking caliper. 

Either put a caliper seal kit in it, or give it to someone who can fix it or use the parts.

In fact, I'll pay the shipping if you don't want it (I need a new piston for a caliper I have sitting here).

I would guess that you need to bleed the entire system, because the master cylinder went dry.

Are you pumping the brake pedal, using a power bleeder or a vacuum bleeder? I'm guessing your trying to bleed by pumping the pedal. From my experience, that doesn't work too well when the master cylinder is dry. You might have better luck with a power bleeder (you can make your own for about $20, see the article on Dan's Site), or even a handheld (MityVac) vacuum pump.


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## Corradoman8 (Sep 14, 2000)

I'm definitely keeping the old caliper. 

I've bled the entire system. I was using a Craftsman power bleeder/ vacuum checker. I'm taking the car next week to a friend who had a shop about 20 minutes from here. I don't think of myself as a pro when it comes to brakes...but how could the master have gone dry when the resivior is full of brake fluid????


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## germancarnut51 (Mar 23, 2008)

Before the rear caliper failed, was the parking brake 100% functional or was it soft? If it was soft, did you try tightening up the rear brakes by adjusting the brake pad clearance by pumping the parking brake handle? It can take over 200 full strokes to bring the brake pad/rotor clearance to spec (with properly adjusted parking brake cables) after a caliper or pads or rotors have been replaced in the rear.

If you blew fluid onto the ground because a caliper seal failed, the lost fluid had to come from somewhere, so the reservoir could not have been full still. The master cylinder has two separate fluid pressure circuits to lessen the chance that in the event that you have a brake failure, that al least part of your brake system will operate. So, it's possible for one side to fail/leak, and go dry, while the other continues to function.

Are you bleeding the brakes with the car on the ground, or with the jackstands placed to hold the rear axle in the same position it's in when the rear wheels are on the ground? If not, the rear mounted proportioning valve will restrict fluid flow to the rear brakes, and you won't be able to get good fluid flow, and eliminate the air in the rear brake lines.

Sometimes it's really tough to get fluid flowing all the way through from the master cylinder to new, dry caliper (especially when the brake pads are new and the caliper is bone dry). It's easier with the caliper piston extended (which is a reason why I recommend replacing the brake fluid before installing new brake pads). What you can try is removing the bleed valve completely, and inserting the vacuum bleeder hose directly into the hole, and pumping the vacuum pump like crazy to get the highest fluid flow rate to can.

What I would do if I were you, is check for brake fluid leaks on the car, top to bottom. If you discover that you are leaking brake fluid, but their aren't any visible leaks, it's possible that the rear seal of the master cylinder has failed, and the fluid is leaking into the vacuum booster. 

After determining if there's a leak, and correcting it, then, do a complete system bleed/fluid exchange using at least 1 quart of brake fluid with the car on the ground, to see if the brake pedal firmness can be recovered. If not, I recommend replacing the master cylinder. You can get a Meyle brand, alloy body master brake cylinder for about $45 from Autohausaz.com (free ground shipping on orders over $50, so find something else you need, or a few inexpensive spare parts, like oil dipstick tubes or oil pressure sensors).


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## Corradoman8 (Sep 14, 2000)

my parking brake has always been very stiff.

the fluid was coming from the bleeder/banjo nipple. The fitting was cross threaded at some point so every time you put your foot on the brake, fluid would come up through the fitting and spray all over the side of the gas tank and pool in the rear sway arm. 

There is fluid in my reservoir. While the level has gone down considerably, I am still able to see the fluid is still in there. Unfortunately I have the Seabring wheels which do not allow enough clearance to get to the fitting to bleed the calipers on the ground, so I have been using jack stands. not that you've mentioned the rear proportioning valve, I have noticed a squeaking noise coming from the valve when the brake pedal was fully depressed. That noise was only heard after the first round of bleeding during the two day period that the brakes worked normally. I've ordered a new spring for the valve as the original looks like its been through hell and back.

I did have the car on four jacks stands and I went from both rear wheel all the way to the master cylinder and again from the fronts to the master. I haven't checked the booster yet and the new master cylinder and reservoir are completely dry on the outsides. There is still residue on the transmission from where the master cylinder failed and separated from the brittle original reservoir, but no new fluid collection. Like wise, I checked my fronts. I even had a neighbor sit in the car and tap the pedal a couple times to see if i had any seepage from any of the lines.


I've looked in the Bentley manual but I came away more confused......is there a way to "tune" the rear proportioning valve? The replacement valve is made by ATE and it looks as though the nut that attaches the plunger to the internals is welded on.

Thanks for the help!!:beer:


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## germancarnut51 (Mar 23, 2008)

I have Sebrings on my Jetta GT (had to make room to clear the G60 front calipers In installed) as well, and I haven't gotten around installing my lowering springs yet, so I can esily get under the back of the car to bleed the rear calipers. I bleed the rear calipers on my Golf with H&R Sport springs the same way.

So when you had the car on four jackstands, where did you put the rear stands? Under the body, or under the rear beam. If you put the stands on the rear beam, the stands will hold the rear beam where it's positioned when the rear tires are on the ground. There's also a way to move the lever arm (and hold it) on the proportion valve so it will act like the car is on the ground, but I don't remember how to do that without crawling under the car to jog my memory. 

The only thing that can be adjusted on the proportion valve is the location of the spring (which holds the lever arm on the proportioning valve at "neutral" position). I've noticed that cars that came lowered from the factory are adjusted differently from those that were sold at standard ride height.


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## Corradoman8 (Sep 14, 2000)

I'm pulling my hair out with this thing. I blead the system again and got no bubbles....just fluid. I had the jack stands positined on the rear beam. STILL NO PRESSURE. 

I replace my broken sping on the proportioning valve and theres slack. I have it adjusted all the way out and the spring does nothing. I've called a guy that was a VW factory G60 guy back in the day. He's got the toool to adjust the proportioning valve. i'm taking the car to him to get him to see if theres something else I've missed. 

My last guesses are that the BRAND new master has gone bad.


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## germancarnut51 (Mar 23, 2008)

Where did the brand-new master cylinder come from? What brand is it, and was it really factory new, or a rebuild.

Forty years ago I used to rebuild brake master cylinders when necessary, and I good good results. Eventually I stopped because the price/cost of OE master cylinders dropped down close to the cost of a rebuilt master cylinder or the cost of a quality rebuild kit.

But, I'm not sure I trust the quality of the inexpensive aftermarket master cylinders. Some of them are high in quality (I've used Meyles, and they are excellent), and I've seen some dirt cheap ones for sale (KMM brand comes to mind, selling for about $27 last time I checked) that scared me when I saw photos of them. OE ATE and Girling master cylinders are like $125-$175, and always a safe bet.

Maybe the master cylinder you got was on the shelf too long, and the rubber seals dried out?


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## Corradoman8 (Sep 14, 2000)

I dropped it off at a shop yesterday. its to cold to work on it and i'm beyond bewildered.


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