Topic: I don't have time for this. Major Brake problem. Help

[GrimReaper]

86 4 runner bone stock. When I was shopping for a runner how well the brakes worked on this one was one of my things that caused me to buy it. THe brakes were junk onn all the others I drove and great on this one.

I just changed jobs and went into sales because my job of 11 years was axed. Not happy about sales but I have a wife and two kids to feed so cant really be without. Also I am vested so really don't want to loose that now that I am pushing 40.

 So now I work 3 weekends a month and I'm on closing shift for this week and next. I am going 8 days straight between my days off this week. I leave for work about 10:30 and get home at 8:30 well after dark. My garge is slap full of 1959 Caravanner so I have to work on it on the slopped drive. I REALLY DON'T HAVE THE TIME FOR THIS.

 Came home from work last night and everything is fine. Hop in it to head out for work this morning. Get half way down my street come to the second stop sign and hit the brakes. Peddle is suddenly very high, hard and not slowing the truck like normal. I press harder and I get a pop the peddle drops to a more normal point one of the back wheels locks. You can hear and feel the pop. Does it every stop from there.    I come back to the house and park it and took the wife's car to work.

 Anybody had a simular problem and can tell when to start on sorting this out? I really don't need to do a all night wrench fest on this thing.

 I can only come up with a couple things I think 'Might" cause this.
1 Something screwed up in one of the adjusters like maybe a broken return spring.
2 something hanging on the parking brake. Its not cold enoough for lquid in the cable to frees. Only down to low 50's last night. 
3 load sensing valve maybe but really the symptoms dont seem what I would expect from a problem with it.

Any ideas would be greatly appreciated.

Thanks in advance.
 

[Mike D]

It sound like your brake booster is sticking or that could just be me.

[brainlessfool]

Rear brake flex hose is a maybe. hard to tell without driving it my self. 

[GrimReaper [OP]]

Rear brake flex hose is a maybe. hard to tell without driving it my self. 

Hmmmm It feels mechanical. Its like a brake shoe is hung and you appley enough pressure and it get past what hung it with a pop. Hose problem I don't think would act like this.

MikeD's idea with a booster problem is possible. Maybe the valve is not working in the diaphram. It really felt like it was at the back axle but this happend and within three minutes I was in the other car headed to work. I'll have a hour or so to play with it in the morning tomorrow and try to diagnose it better and get it up to the garage so I can pull it down when I get home. Then I have to go to work.

[brainlessfool]

I'd pull the side that locked frist. but don't discount the hose. if there is a pice of rubber come lose inside the hose it can do what your talking about. but again with out driving it myself it's realy hard to say. all I can do is give things that "might" act this was. good luck. 

[GrimReaper [OP]]

It sound like your brake booster is sticking or that could just be me.

Well starting to sound more like you are right.

Got to do a little diagnostic time on it before work today. Engine off I could repeat the problem. It felt like it was in the peddle but you could hear the rear brakes squeak as it ovecame what ever is doing this. Did it 15 times or more. So I started juggling cars to get it up to the garage so I could tinker on it tonight when I get home. Started it and it happend. I pumped the brakes a few time and it stared getting less and less. Did a couple loops around the block hammering the brakes and its gone. 


Drive it to work today and see if it comes back.

Basically it feels like your hitting the brakes with the parking brake on. Peddle high and hard because they are already up. Then suddenly it drops with a pop and you hear the rears activate.

Maybe I'll pull the check valve off the booster and see if I can shoot some WD 40 in there at the seals on the shaft and valve.

Any check valves in the load sensing junk?

 I'll go through the back brakes Thursday and verify no problems back there and check the linings and adjusters. I plan to add a a leaf to each side that day any way to take care of a sag problem. Its daily hitting the bumps stops on the hwy EMPTY. 

[BigMike]

.......but even if it was the rear brakes, you should still have a normal pedal feel because the booster is there. The only time the pedal should feel so heavy is if the booster is not boosting... right?

[GrimReaper [OP]]

Well peddle hight can be changed with the rears when the ajusters are not working or some knuckle head turns the drum beyond spec but the feel is normally all booster unless air in the lines. So yes thats pointing back at the booster again.

I still question that load sense stuff. I don't understand how it's plumbed. It has a return line back to the distribution block in the passengerside fender.It appears the return goes back into the front circuit.

 My Burb has load sense but it's just a Prop valve on the single line. No return line. I don't understand the purpose for the extra line.

Well still acting normal after an another 30 miles. I'll go over it all in a couple days. I hate weird problems like this. they nag at me wondering if they will be back. 

[WHITE_TRASH]

when in doubt get rid of it.  Pull the load valve off the runner, plug the return line at the distribution block and just get one from summit for $40.  It will save you a helluve lotta headache.