Helpful Brake Hint.

James Seahill said:

Have you discovered the virtues of a vacuum pump for bleeding brake lines?

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Have a home made power bleeder that works like a champ 10 minutes and all Brakes are bleed.



But I have also discovered that the Rear Wheel Cylinder that O'Reillys sells are badly manufactured, and will not bolt up to the Backing plate.

James Seahill said:

there's a regulator mounted to the left front fender that all four lines tie into---on pickups there is another unit mounted near the rear axle--maybe one or the other isn't doing it's job

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ORCoaster said:

I have an 81 Pickup and they did away with the rear unit on that one. They went to a different setup. I ordered a new MC as I could pump up the brakes and hold my foot on the pedal and it would just collapse pretty steady to the floor.

Going to remove it tomorrow as AutoZone just shipped the MC today. I need to beat the rain.

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That was a load sensing proportional valve, the more weight in the rear it opened a little bit more, Very common on large vans as I had one on my 92 Caravan that was part and parcel of the right rear leaf spring, you had to replace the Spring to replace the Valve... ok caught me, my 92 dodge had electronic braking that failed, and every time it was 400 bucks to repair it..(dealer only). So Since they discontinued the experiment in late 93, I went and got all the parts off a 94 (Calipers) Leafe Spring Brake lines, Vacuum Booster, and back to MC to replace, and for the next 150K I never lost my brakes.

VW did the same thing on Trucks and Cabriolets, the Caveat is that in 81 US Caddy's didn't have this installed...Late 83 and up I think did. They aren't that expensive
Just a Pain in the Keister.

On a side note my son called and said the Brakes were very spongy......... Validated that my MC was Warrantied, but opted to bleed them again, and found that my ho-made bleeder broke in the Middle of the First bleed... (the trigger broke and the valve didn't fully work....ok, 14 dollars later) and a re-bleed couldn't believe the amount of air I sucked out of the opposite side that I really repaired, so I suppose it broke between the switching from left front/ right rear, to right front/left rear....

So he has great stopping power now again....

I haven't taken the drums off but I don't see any liquid dripping down from them and it has been parked in the same spot for a week. I replaced the wheel cylinders when I did the brakes about 4 mths ago so I am hoping they held up ok with the new MC.

I was going to reverse bleed the lines as that might get the air out of the MC if indeed there is some there. I used a Mighty Vac system to pull a vacuum from the wheel cylinders the first time I bled them. Had a heck of a time getting fluid through them. That is why I was wondering if I could do something other than one of those plastic nuts that replace the switch on the proportion valve. I used to have a car that had a little bit of a stem that stuck out of that valve and you would pull it out a bit and slip a clip on a slot and it would hold it full open.

I had my wife do the pump and close as a second try at bleeding the air out but it really didn't do the job. I know from experience that sometimes the orientation of the car makes a difference or the position of the MC relative to the level of the brake fluid can make air get trapped in and no amount of bleeding can get it easily.

I was also thinking of starting with the lines at the MC as suggested here. Why not try the easy button first eh?

Thanks for the confirmation and hints. No brakes are preventing me from putting the turbo on at this time.

Rain let up enough to get out a tarp and get under the offensive truck. First however I used a 2 oz syringe and made sure all the air was out of the MC by squirting a couple of shots through the extra 2 ports that are blocked off with nuts supplied by MC manufacturer. I did see some bubbles out of that work.

Then I crawled under to the rear brakes. I used the Mighty Vac system there and really didn't think I had much of a difference. I collected about an inch out of each cylinder and it felt like I had a good solid pedal after that. I couldn't pump it up and hold it much higher than the initial first step down on it.

So I fired it up and took it for a short trip around the block. Brakes did not heat up or grab more so in the front than the rears. But the pedal does go to the floor on the initial step and my vacuum gauge drops considerably when that happens.

I jacked the rear end up in the drive and then started the truck. I could spin the tire by hand enough to then step inside the truck and push on the pedal. It would go nearly half way down before I would see the tires try to slow down.

So I think it is the free play in the booster that needs to be adjusted. If I make the shaft longer then there will not be as much travel on the pedal before it hits the pistons. That is what I think is happening.

Any other opinions out there? Would love to hear them. Just hoping I get another break or two in the rain tomorrow. This inch or two a day stuff makes not having a garage a real pain.

I have been looking into several proportioning valves that might replace the one on the truck. Doesn't seem to me that there are any with the right combination. Mine has the two lines coming out of the different bowls on the Master Cylinder and then two lines out to the back. In between the valve is actually two functions in one. First it has the switch on top to show me if one side of the system is doing more work than the other. It kicks a piston over one side or the other and the switch turns the BRAKE light on the dash on.
There are two pistons with O rings and what look to be rubber washers and a spring in each cylinder. I have read someplace that these pistons regulate the bias or amount of fluid to the rear brakes to keep them from locking up on a hard stop. Hence proportioning the fluid between the rear and the front discs. I have read and don't exactly know that it is true that these same devices keep a little bit of pressure built up on the rear cyclinders so that your foot doesn't travel as far to the floor when you first step on the brakes after not using them for a bit.

Can anyone verify that is the case? I know there are after market valves that keep a bit of pressure like that but I am not sure that is the case for our VW's.

I have found several Wildwood valves in the aftermarket area but I don't think they will do all the jobs that the original is designed to do. Then there is the issue of controlling both rear wheels and having the switch work.

I think rebuilding what I have is the only way to fix my brake pedal travel problem. That will require cutting the lines from the back of the car as there is just no way to work in that area on the fender. I already tried that and didn't like the result. I would just detach the lines going to the top of the valve from the MC as those already are loose. I then will need to splice the rear lines back together after rebuilding or replacing the valve.

Might be time to invest in stockpiling those valves. I bet most folks scrap their cars with them on. They are NLA. And no good aftermarket subs either.

The standard Westy build has a single proportional valve on the inside fender to the right and below of the master.
It takes the 2 lines and splits them off 4 ways IIRC.

The purpose of the proportional valve is to reduce pressure to the rears so they don't lock up on braking.
As far as I know they don't hold any residual pressure, and are a Spring loaded valve arrangement.

You can upgrade to the 22MM MC off of a Cabriolet, and that has 2 proportional valves on the MC itself, where the Brake Pressure light is controlled through a Brake Fluid is Low sender in the cap of the res.

The res is different as well as the MC has 4 Brake lines attached to it.

Some of the Tween versions have a Load Sensing Proportional Valve located on the rear axle that accomplished the same thing but based on the load on the rear axle.

With the advent of the Cabriolet later 83 they went to the larger MC, Vented Rotors. Which decreased Brake Fade and better wear of the pads on the front.

The rears and the fronts are on diagonal Circuits so that you can brake straight, they are left front right rear, and right front left rear, it isn't that they are one for the front and one for the rear. So don't get conflicting information. You can do away with them sort of by using separate proportional valves from the Cabriolet in-line with each rear, but you still would need to diagonal the circuits.

typical mc set up with the load sensing at the bottom, and the proportional valves for that set up are still avail overseas.
Pricey: https://www.vwheritage.com/841612151-brake-pressure-regulator-vw-spare

Partsplaceinc.com may have a Westy proportional valve as used, but I have heard mixed things about them. It would be best to email them first.



84 Golf


Good place to bookmark:
https://volkswagen.7zap.com/en/usa/