Brake system issue... - Page 2

Akimbeau · #21 (**permalink**) 09-22-2017, 08:05 AM

Quote:

Originally Posted by joyridin'

You are talking about adjusting the e-brake lever. I am talking about adjusting the rear brakes to give yourself a brake pedal. The 2 are different.

What you would need to do is back off the e-brake until the lever on the caliper is as far back as it can go, then hit the brake pedal while pulling on the lever.

As stated, there is a ratchet mechanism in the caliper piston that is used to adjust the brake pedal feel. When you crank up the e-brake handle, you are bypassing this mechanism.

Sorry, Joyridin' I wasn't clear. I meant I was adjusting the e brake lever(arm) AT THE CALIPER. The procedure I've been using is to remove the arm(lever) and reinstall so there is some play, then with the return spring installed and a pair of vice grips firmly attached to the arm I pull the vice grips and arm to the fully on position and then quickly release so the arm snaps back to actuate the internal adjusting mechanism. The desired result is for the arm to be 1/4" from the stop for the e brake to lock up. This is all per a tech bulletin I found on line. I'll try your procedure for adjusting the calipers and see what happens.

Thanks everyone for all your ideas!

Akimbeau · #22 (**permalink**) 09-22-2017, 08:50 AM

So I tried the adjustment procedure mentioned by Joyridin' with no change in symptoms. I also tried shimming the outer brake pad to compress the piston further into the caliper body, no change. Should I consider a 10lb valve like is used on drum brakes?

Kim

RockBit · #23 (**permalink**) 09-22-2017, 01:49 PM

Kim:

Google 'GM metric disc brake adjustment'. You will see a thread on JalopyJournal where a guy had your problem. He discovered his calipers were low drag, which look the same as GM metric calipers. He changed the out for standard GM metric calipers and it fixed the problem.

cycleguy55 · #24 (**permalink**) 09-22-2017, 04:54 PM

Quote:

Originally Posted by EM-0785

Cycleguy55,
Question on the speed bleeders. I had bought multiple bleeder sets for my rear Girlings. Non check valve version for use in reverse bleeding/flushing if/when needed and check valve speed bleeders left in afterward for regular maintenance.

On my new front Wilwoods I didn't install bleeders there (yet, wanted to) with concerns of others on the web having issues damaging the threads/seal with speed bleeders on their Wilwoods.

I don't believe Wilwood sells them (maybe?), but do you have a brand you like or any specific advice/cautions in that regard? Maybe the others were just not careful to really ensure the right bleeder dimensions (easy to figure)?

Those like myself, and perhaps the OP, could benefit from any thoughts there. Thanks, Brent

The thread size is 1/4" x 28 TPI. I know Wilwood shows bleeders as 1/8"NPT, but that's a bushing with an internal size of 1/4" x 28 TPI. You'll need a pair for each front caliper - installed as replacements for the upper bleed screws. You can leave the lower bleed screws in place.

If memory serves me correctly, my speed bleeders are Russell. I had no problem stripping or damaging the threads in the calipers, but I was careful to ensure the threads were engaged properly before putting a wrench on them.

EM-0785 · #25 (**permalink**) 09-22-2017, 06:48 PM

Quote:

Originally Posted by cycleguy55

The thread size is 1/4" x 28 TPI. I know Wilwood shows bleeders as 1/8"NPT, but that's a bushing with an internal size of 1/4" x 28 TPI. You'll need a pair for each front caliper - installed as replacements for the upper bleed screws. You can leave the lower bleed screws in place.

If memory serves me correctly, my speed bleeders are Russell. I had no problem stripping or damaging the threads in the calipers, but I was careful to ensure the threads were engaged properly before putting a wrench on them.

Brian, thanks much!

Kim (Akimbeau), best of luck, sounds like you're narrowing it down with some very good advice from others.

Brent

Akimbeau · #26 (**permalink**) 09-24-2017, 09:14 AM

I resolved the issue. It was not air in the line, Joyridin was correct that it was the caliper e brake adjustment. What I was doing wrong was that you need to first fully depress the caliper piston with the e brake adjustment all the way out. This allows the piston to start as far back into the caliper as possible, expelling excess hydraulic fluid. Then you adjust the e brake mechanism to take up all the excess pad gap. THis allows for the minimal amount of hydraulics operating the brakes. Unfortunately the instructions I was following did not include this step in the adjustment procedure and I had to figure it out on my own. My brain hurts...

Thanks to all for your help!

Kim

hotrodyankee · #27 (**permalink**) 02-01-2018, 11:07 AM

[quote=joyridin';1430668]You are talking about adjusting the e-brake lever. I am talking about adjusting the rear brakes to give yourself a brake pedal. The 2 are different.

What you would need to do is back off the e-brake until the lever on the caliper is as far back as it can go, then hit the brake pedal while pulling on the lever.

As stated, there is a ratchet mechanism in the caliper piston that is used to adjust the brake pedal feel. When you crank up the e-brake handle, you are bypassing this mechanism.[/QUOTE

hotrodyankee · #28 (**permalink**) 02-01-2018, 11:19 AM

joyridin, I just put on the Eldorado calipers on my car, and have the same problem. I am looking to adjust the brakes not the e-brake. when you say to back off the e- brake until the lever on the caliper is as far back as it will go, do you mean the lever stop on the caliper, or the other direction? Also is this done on the car? Any help explaining this to me will be a great help. Thanks, Mike.

joyridin' · #29 (**permalink**) 02-01-2018, 01:59 PM

Quote:

Originally Posted by hotrodyankee

joyridin, I just put on the Eldorado calipers on my car, and have the same problem. I am looking to adjust the brakes not the e-brake. when you say to back off the e- brake until the lever on the caliper is as far back as it will go, do you mean the lever stop on the caliper, or the other direction? Also is this done on the car? Any help explaining this to me will be a great help. Thanks, Mike.

If they are new calipers, you probably will not have a problem. First, the caliper piston needs to be all way to the bottom. If the caliper is new, we can assume this is the case since you probably would not have gotten the caliper with pads over the rotor. If not, you need to remove the caliper and pads and screw the piston all the way down until it bottoms out. Next, the easiest thing to do is actually leave the e-brake cable unhooked. Bleed the brakes and remove all air. Then pump the pedal hard. There is a ratchet mechanism in the piston that will ratchet the piston out and take up the extra play giving you a good pedal. After that is done, then hook up the e-brake cables. If you have the e-brake adjusted too high, the rotors will not turn. Just back off the adjustment. Sometimes you might have to drive the car a bit to get the pistons to ratchet out if there is a pretty big gap to take-up.

hotrodyankee · #30 (**permalink**) 02-01-2018, 03:22 PM

Thanks for the info. The calipers are new. When I started to assemble everything on the car, I had to back off the lever[small amount] to get the pads over the rotor then re-adjusted the e-brake. As it is assembled now, there is a 1/4" gap between the lever and the lever stop when the e-brake is applied. Drove the car for a bit today[35 degrees out] didn't seen to stop that well. The calipers I replaced were the wilwood single piston style that look like a GM metric, and those stopped good, but with no park brake provision. Thanks again!

Gaz64 · #31 (**permalink**) 02-01-2018, 08:42 PM

Quote:

Originally Posted by RockBit

If you had air still in the system, the pedal would not get firm on the second pump. It sounds like you have bled the system adequately.

A residual pressure valve is made to cure the problem you are describing, and you have added one to the rear brake line. Either you have installed it backwards, or the one you have is leaking. Either condition will allow your rear pistons to retract too much and give you more pedal travel on the first pump. Since the second pump is firm (the rear pistons have not had time to retract) my guess is your residual pressure valve is leaking/faulty.

I would try a new residual pressure valve. My 2 cents. Good luck.

Yes, certainly sounds like pads backing off.
I would check all wheels for disc pad drag while the rotating the wheels before and straight after pumping the pedal up.
That will show you which ones where retracted too much first up.