Need brake advice

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Hoosier Daddy

Hoosier Daddy

SILVER Star
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Joined
Jul 1, 2005
Threads
75
Messages
1,344
Location
CO Springs
1995 FZJ
131k miles

Replaced front pads with aftermarket Wagners because the OEMs squeaked so much. At the same time I replaced a rear caliper that wad frozen, with an OEM rebuilt caliper. I bled the caliper afterward.

When I went to test drive, the brakes were very soft and braking was poor. I re-bled it thoroughly with modest improvement. Fearing that compressing the front pistons had led to master cylinder seal damage, I put on a new Aisin MC and bled it again. No change, still dangerously soft and weak brakes. I then took it to Goodyear (open weekends) and had them bleed it. It improved but the pedal still sinks to the floor when the engine is running (firm with the engine off) and the brakes are not as strong as they had been before. It went from dangerous to just bad.

I'm tired of screwing with it and want to know if anyone has any new ideas or if anyone has a particular shop in the Springs they would recommend to work on this brake problem.
 
BTW when I talked about bleeding the brakes, I did all calipers and LSPV in proper order.

My next effort will be to replace my SpeedBleeders with the original bleeder screws and bleed it again, in case that is preventing a good bleed.
 
Seems like the pedal going soft would have to be a bad master cylinder, air in the system or a leak.

I had some soft pedal brake problems a couple of months ago. I was using a vacuum brake bleeder and couldn't get a consistent bleed on the rear calipers. I had to put thread sealant on the caliper bleeder screws. Still had problems so I replaced the POS Napa remanufactured MC with a new unit and everything works great.
 
It sounds like you're doing everything right. Sucks that it still won't work. I've been there. I figure your calipers are on the right side, but it's still worth mentioning. Bleeder screws are up right? Did you bench bleed the master cylinder with it isolated from the system?

Also, might be a long shot in your case, but last year I went through this and it turned out to be a bad wheel bearing on the front. The drivers side bearing was so bad, it would turn sideways and force the caliper apart-- then it took a few pedal pumps to compress the caliper and pull the wheel back straight.

I also know what chuck is talking about, when you put a vacuum on the bleeder screws, you get a lot of air around the threads of the bleeders, especially if you have them screwed out too far. I still prefer the old pump, hold, and crack method.
 
black95 said:
It sounds like you're doing everything right. Sucks that it still won't work. I've been there. I figure your calipers are on the right side, but it's still worth mentioning. Bleeder screws are up right? Did you bench bleed the master cylinder with it isolated from the system?

Also, might be a long shot in your case, but last year I went through this and it turned out to be a bad wheel bearing on the front. The drivers side bearing was so bad, it would turn sideways and force the caliper apart-- then it took a few pedal pumps to compress the caliper and pull the wheel back straight.

I also know what chuck is talking about, when you put a vacuum on the bleeder screws, you get a lot of air around the threads of the bleeders, especially if you have them screwed out too far. I still prefer the old pump, hold, and crack method.
Click to expand...


Thing is, it started right when I did the front pads and rear caliper, so I haven't been thinking wheel bearings, but will check that. Replaced caliper is definitely on correctly.

"Pump, hold, and crack" (there's a dirty joke there somewhere) is next, sans the speedbleeders this time.
 
I went through the same thing last year, you have ABS right? You can look it up as well as many other posts in the 80's section. Takes many tries, if it is nothing else as mentioned.
 
Andrew was kind enough to help me try to figure out my brake issue today, with troubleshooting and bleeding again. The bad news is that we only got one tiny bubble out and the problem persists, The good news is that he reminded me (again) to check the wheel bearings. Turns out both sides were pretty loose. I adjusted the bearings but the brakes are essentially unchanged. Maybe it's my imagination though, but the steering seems less sloppy.

I have discovered that I had thrown out my old bleeder screws, so new ones are on order ($5 a pop!) and I am ordering a Mityvac vacuum bleeder that runs on compressed air. I know the hand-operated vacs suck, but people seem to rave about the compressor version. Andrew seems suspicious of my new master cylinder, but I'm still convinced I have air hiding somewhere.

I'll update this thread as things unfold.
 
Is there a fitting somewhere in the middle of the vehicle you can crack? I know the 4runners and trucks have fittings for the rear brakes on the frame rail in the passenger fenderwell. Maybe you could crack the lines at the master cylinder? Need an assistant to do any of this, so and don't let out fluid until the pressure built up is gone, or air could enter the system. This is a messy endeavor, but may help. Brake fluid is right up there with antifreeze on my list of most hated substances on the planet.

Also, I am a faithful Gearz watcher and Stacy David fan, he always uses that pheonix systems bleeder, sends in fluid from the brakes calipers up... makes a lot of sense, that's where the air wants to go anyway. Go to summitracing.com and search "phoenix brake bleeder" Just a thought.
 
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I think I got it figured out. I bled the master cylinder on the vehicle (like the FSM says to do) when I installed the new one. Tonight I noticed that the MC sits at an angle, with the front end higher than the rear. I think air can get trapped in the top front of the MC, which is above the furthest port when bleeding. So I jacked up the rear of the truck and re-bled it. I got a big air bubble out. After reconnecting the lines and bleeding all the calipers, it is MUCH better (although still not perfect). I'll try it again this weekend by parking on a slope when I bleed the MC.
 
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