2 springs on A2 brake pressure regulator

Greetz All,

I recently replaced all 4 rotors on my '86 GTI. After about a week of driving, I noticed that on both rear rotors, there was about a half inch band of surface rust on the inner diameter of the disc, and the machining marks had not gone away like they had in the front. This rust is only on the outside of the disc.

I started poking around and discovered the regulator was seized. So I replaced it along with most of the brake lines. (always a fun job)

So now after a couple more weeks of driving (120 miles a day to work) the rust is still there. I thumbed through the Bentley and found a diagram of the pressure regulator and noticed it only showed the single large spring from the axle to the regulator. Mine has a second smaller spring connected from the bottom of the lever to the large spring itself. An image of the second spring location can be seen here,

formatting link
with the spring connected where the red "X"s are. After reading a bit in the Google archives, I found a few references that say you should bleed your rear brakes with the regulator lever pulled all the way back. I assume this opens the regulator all the way. This secondary spring would seem to hold the lever all the way forward when the car is level so minimum pressure would always be applied to the rear brakes. Is this second spring suppose to be there? I couldn't find any reference to it. Also, the Bentley mentions the regulator is adjustable, but doesn't say how to adjust it. I guessing that with the car sitting level, the top of the lever should be pulled almost all the way back to give room for heavy loads.

Thanks for any info.

Ed '86 GTI (235,000 miles and becoming newer all the time) '01 GLS (55,000 miles and no problems)

------------ Get Firefox!------------

Reply to
Mr.Eddy
Loading thread data ...

Reply to
Eric Rupert

Now the poor guy's gonna find that his rear calipers are seized too :(

nate

Eric Rupert wrote:

Reply to
Nate Nagel

Care to elaborate on why they seize, and if they are, what can be done.

Ed

Nate Nagel wrote:

Reply to
Mr.Eddy

If they are seized, you replace them. Usually caused by by a failing master cylinder or related pressure regulator

Reply to
Biz

If your regulator was busted and not letting pressure to the rear brakes, they may have seized from disuse if you didn't use your parking brake regularly. When you get it back together you'll be able to tell quickly if they are or not; if they are new calipers are still available.

good luck,

nate

Reply to
Nate Nagel

Are you all talking about the Brake Proportioning Valve? I have handled several that have seized, but it was the activating arm that seized in the pivots. Some yum-yum juice (my favorite rust penetrant) on the pivots along with some movement of these arms and all seems fine. I just handled one yesterday on a 92 Jetta Carat along with the rear brake cylinders and shoes. I also noted that I had to exert great force to initially bleed both front calipers with the bleeder nipples completely out of the caliper. Then my pressure bleeder would function properly. This I found ODD!

Or is this something else you are talking about?

later, dave Reminder........ Before you criticize someone, you should walk a mile in their shoes. That way, when you criticize them, you are a mile away from them, and you have their shoes. Frieda Norris

Reply to
dave

When I replaced the rotors, I also did the seals and dust boots in the calipers, so if by seized, you mean the piston seized in the caliper, they weren't.

So it looks like I made out OK.

Ed

Reply to
Mr.Eddy

Looks like I have the rear brakes working now.

I adjusted the big spring on the arm so the regulator lever is pulled almost all the way back with me sitting in the seat and the car level and bled each caliper a bit more to make sure.

I actually put the small spring back in after I got this adjusted, because the regulator lever wouldn't really pull forward when I'd raise the back of the car simulating a hard stop. So now the small spring makes sure the lever is pulled forward and the big spring pulls it back.

Seems to work good, after a short test drive, both rear discs were almost too warm to touch, and stopping was noticibly better. I found a patch of dirt covered road and was able to lock up the rears under hard braking, so I know they are working.

Ed

Mr.Eddy wrote:

Reply to
Mr.Eddy

Good stuff. You may wish to readjust it so that the fronts will lock first under a normal load, however, as that is a more stable condition (and the reason for the prop valve in the first place.)

good luck,

nate

Mr.Eddy wrote:

Reply to
Nate Nagel

You should NOT be able to lock up the rears before the fronts.

A vehicle is extremely unstable with the rear wheels locked.

Reply to
Bernd Felsche

I guess I should have stated the fronts did lock first, but I never said they didn't lock either.

I think I have them adjusted about right, it took quite a bit effort to get the rears to lock.

Reply to
Mr.Eddy

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.