So my buddy and I are trying to fix the rear brakes on a 85 Fiero and we thought we only needed to replace 1 rear caliper. Well 3 calipers later (all rear) and new parking brake cables and the car hardly brakes. The one caliper ended up stripping the threads from the first banjo bolt before getting to 30 ft/lbs, we got to 30 once but it kept leaking we replaced the crush washers and around 20 the bolt suddenly got very easy to turn.
We have fully swapped out both rear calipers and bled the the fronts and the backs and even did the master bleed kit with the hoses where it just goes in a loop until the hoses stop pulling bubbles. I will also note the old system, was likely DOT 3 and my partner opted for a mix of DOT 4 Sythetic and Max Synthetic (whatever that means). We dont believe there should be much of an issue there and that we only would have seen issues if we did DOT 5. We are about 3 or 4 bottles into this whole ordeal.
We have also completely replaced the parking brake cables and equalizer nut.
So my list of questions are:
1. How much gap should we see in the rear brake pads while resting?
- I havent measured but I would say we are at maybe 3+ ish playing cards total on driver side and maybe 2 ish on the passenger.
- I will update a better measurement tonight.
2. How much stopping power should the parking brake afford us?
- We can definatly still move the wheel at half pull and at full pull the wheel will mostly fight us to spin but can still be spun with out the wheel on.
3. Is that trick in the Ogres cave really that useless to try where you prop out the piston by the dust boot and try to tighten the arm with the spring on it?
- It seemed to help on the passneger side even when I did it wrong and I will have a better oppotunity this evening.
- That driver side sucks to tighten, any tips to keep thatarms from moving while tightening?
4. What might make both bleeders still leak out the threads just a smidge?
- We clean the hell out of the area with brake cleaner, do some work, then go up and down the drive way a few times and there still appears to be some small amount of brake fluid at the pit of the bleeder threads. Do you think we still have a bad control group or you would expect that?
5. Will the bleeder threads still leak if there is air in the system?
- My father who has worked on many cars successfully claims if there is air still in the system then stuff can leak from everywhere, but we just keep bleeding and see no bubbles.
6. Is there some process we need to do to calibrate the pistons?
- My friend claims that he read somewhere that there was some process you need to do with pressing on the brake or something while working the parking brake to get the piston to auto adjust to be correct.
7. How much slack should the parking brake cables have at rest?
- We have tried heavy slack, no slack, some slack, pretty taught and the parking brake just alwasy allows us to hard turn the wheel.
8. Would tightening that arm with the spring on it on the caliper help or hurt how much the piston moves when the brake or parking brake are engaged?
- I know the arm is only supposed to move about 1/4" but one side definatly moves more than the other and they both move at least a 1/2" and we can still move the wheels.
9. Wouldn't I expect to see the front resevoir go down at a diminished rate compared to the back but still down if the master was leaking anywhere into the booster or elsewhere while we are bleeding the brakes?
- We have another friend who is insistant that the booster is bad, but I fished a ton of string into the booaster and it came back dry. The booster also seems to hold pressure fine inbetween sessions. The check vavle seems solid and you cant blow backwards into it. The brakes get noticeably softer when the car is turned on and get stiffer than they were with the car on when the car is off.
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MJM
