Brakes...grrr....

RatLabGuy

RatLabGuy

You look like a monkey and smell like one too
Joined
May 18, 2005
Location
Churchville, MD
Having brake issues. '89 4Runner.
When I first press pedal, it goes almost all te hway to the floor; Will stop, but way longer travel than normal travel. If I pump a few times, it builds pressure and feels normal.
but if I let off and wait a minute, it will do the same again. Both w/ engine off and on.
Now, if I pump and hold, it does NOT seem to lose pressure.

A little perplexed.
I've bled all four corners and LSPV, even replaced the MC. The MC needed replacing anyway b/c it has had a small leak at the resovoir (for about 3 years lol).
Could there still be air in there somewhere? No leaks that I can find; if it was an outward leak, it wouldn't hold pressure while holding it pushed in, right?
Could it be a really small leak just letting air in?
Anybody know what the complete fluid volume of thsi system is? E.g. how much minimum to have it all flushed out?
 
Brakes can be very frustrating, indeed. It sounds like a bad MC to me, but you've already replaced that. What kind did you use? It may still be bad. Did you properly bench-bleed the MC? I've heard some people say it should be bench-bled while installed on the firewall to keep from over-extending the piston. Have you tried a power bleeder? Did you replace the flex lines? It's probably time anyway.
 
catfishblues said:
Brakes can be very frustrating, indeed. It sounds like a bad MC to me, but you've already replaced that. What kind did you use? It may still be bad. Did you properly bench-bleed the MC? I've heard some people say it should be bench-bled while installed on the firewall to keep from over-extending the piston. Have you tried a power bleeder? Did you replace the flex lines? It's probably time anyway.
Click to expand...

Its was an AZ reman MC. I replaced it with... unfortunately... another AZ reman. Not my preferred choice but $$ is little tight, and that was free vs alot for the real Toyota deal.
Yes, I bench bled. Then I went ahead and re-bled all the lines again, rear R, rear L, front R, Front L.... doing the last one, I heard the dreaded GRUGLE from the MC... AH SHIT I let it get low... went back and ddid all 4 + LSPV again. Pulled nearly a full can (quart?) through it. Been using a vacuum pump, easier to do by yourself that way. No replacing lines (yet), all are hard except at front, about last 9". No signs of softness or rot on them though.
Since all that, it only takes like 1 extra pump to get normal feeling pressure; holding it in or riding the brakes builds/holds perfectly fine. Of all car work I hate brakes the most.
 
Of the bad lines I've replaced, none of 'em really looked bad from outside. I have pulled apart a caliper before, though, and found pieces of line inside the piston. I replace them fairly frequently. It's recommended every two years. I like to do them when I'm getting a vehicle on the road or doing any extensive brake work. I need to do the Saturn, but I just don't care about that one! ;) They're relatively cheap insurance.
 
adjust the rear shoes

or clean the adjuster so it will self adjust.

the first pump moves the shoes to the drum, the second seats the shoes to the drum, feels spongy because the front and rear brakes ar linked together at the LSPV

Had same issue on my '85, '87, and '90

rear shoes adjust by lightly pulling the parking brake while reversing slow ly, takes multiple times for it to happen, easier to hit the knock outs and use an adjusting spoon or flat blade screw driver on the star wheel.

Also may want to check front wheel bearing adjustment, loose bearing can cause rotors to lean a bit (don't take much) which spreads the pads, first pump straightens things up, second does the deed.
 
Hmmm... will look into that. Probelm started while romping through muck at Rausch Creek, maybe I got some crap in there...
 
X2 on adjusting the rear brakes.
I also just changed the master cylinder on my 89 Toy P/U last week because it was leaking out the seals. Bought a reman. from Napa and spent most of the day trying to get the air bled out (bench bled it) I took it off and put it back on so many times I thought I was going to have to put a zipper on it. The rears would bleed out but fronts wouldn`t do squat. I even took the reman apart to see if the piston was stuck. Come to find out that the front piston wasn`t returning to the rest position because it was trying to suck the brake fluid from the brake line and not the reservoir. Took it back to Napa and had them order me a new one.
 
After spending a day having the g-friend pump the brake pedal on a bum master cylinder I started reading several threads and forums about power bleeders and came up with this. I have a nitrogen tank in the work van so that`s what I used.
ai26.photobucket.com_albums_c128_jetprwler_132_3234_IMG.jpg
 
Nice design. How hard is it to top off the res, though? What I like about the Motive or garden sprayer type is that you have a constant supply of fresh fluid going into the res.
 
Yeah it would have been nice to have a steady supply of brake fluid but I`m to cheap to buy the motive and read that using the pump up sprayer was a little messy(?)
I spent less than $10 for the coupling and fittings. The guage I already had. All I had to do was loosen the clamp, remove the coupling from mc and pour in fluid.
Sorry for the thread hijack. Hope the info helps
 
Having purchased several toyota AutoZoo master cylinders for brakes and wheel and clutch slave cylinders, I can tell you I no longer purchase them from AZ or AA or any of the zippy-rip parts stores. I went through 3 clutch MCs and two slaves before I finally said screw this and went to the dealer, and got a pair that worked first time.

Some of the chain autoparts store stuff is good, some is not. My finding is that their brake stuff is crap.
 
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