Im in need of help. I am having trouble with my brakes not working properly on my 1988 4runner 3.0L V6. They worked fine before i lifted the truck. Found a bad wheel cylinder so i replaced both of them. Switched master cylinders and the power booster off of my other truck. (unless all four of them are bad ) Im still not getting any brakes. When the truck isnt running the pedal gets really stiff like it should but when the truck is running they are really soft and it barely stops the truck. Any help or suggestions would be great. Someone said the proportioning valve, which i think is on the passenger side frame above the rear tire. Not sure if that could be bad.
Last edited by Wilscojeff; 03-11-2010 at 09:50 PM.
Ive bled all four tires and just get fluid. No more air is coming out. It seems like you can feel pressure in the pedal and then as is gets towards the floor is seems like the pressure releases. Almost like a leak but ive checked all the connections and had a buddy look all over while i pumped the hell out of the brakes and we didnt find any leaks.
Ive bled all four tires and just get fluid. No more air is coming out.
Try bleeding the brakes instead of the tires.
Maybe you're not use the proper procedure to bleed them, or the correct order.
The correct order is :
LR,
RR,
RF,
LF,
LSPV
The procedure is to gently pump the pedal 4-5 times and hold it down on the last pump.
Then crack the bleeder open a sec and close.
Then release the pedal.
Repeat.
I just read the forum post on yotatech that you posted fourwd1 on bleeding the master. Very helpful. will try that when i get home from work. Thanks in advance for the help.
Last edited by Wilscojeff; 03-12-2010 at 09:43 AM.
Got the air out of the MC. Still having issues. Good pressure coming out of the front calipers. Very little pressure coming out of the rear drums. There is what looks like a distribution block or something on the rear frame rail above the passenger side tire. Took the brake line off that comes out and goes the the rear brakes and there is very little pressure coming out of the block. Going to pull the one off of my other truck and see if it helps. Thanks for the help and i will let you know how it turns out. Any input would be great. Thanks again.
That should be the LSPV. It regulates pressure to the rear brakes according to load.
Disconnect the rod where it connects to the axle bracket and tie it up to the frame. That should give max pressure if the LSPV is working properly.
Ya i bled it when i did the brakes and straight fluid came out. I ended up just bypassing the LSPV. I plugged the return line ( the one that comes off the front passenger brake line ) and ran the other line straight to the rear spliter. Getting brakes to work now, they are still soft so i think i still have air trapped in there somewhere. Going to attempt bleed again but i took it to elbe this weekend and ran through the mainline and a few other trails.
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