Branden Lawson

Hello all. I apologize for asking what will seem like a very simple question.... But I was just needing some input and Ideas.. I recently had a rear wheel cylinder freeze in the open position and it was causing my rear wheel to lock up... I replaced it and never could get a firm brake pedal... it would stop me great... just really low... if i pumped it once the second push felt great... well upon inspection I found a leak in my rear line by the fuel tank... So to make a long story short... I removed my bed and fuel tank... did substantial rust repair... and ran all new brake lines, minus the ones upfront. I also deleted the LSPV and added a wilwood proportioning valve under the hood. I bled and bled and never could get good pedal... well upon inspection I found that when I would pump a small stream of fluid would run out behind my master cylinder down my brake booster. So I replaced the Master Cylinder with a New one from autozone.

I bench bled the cylinder to an extent that I would consider excessive... because I wanted to be sure.. I connected it and bleed 2 quarts of brake fluid threw the system using the old pump and hold method... RR LR LF RF is the sequence I used... Once again being excessive so i thought I could be certain..
Still the same... Soft pedal on first pump... great pedal on second... I reinstalled fuel tank and with the truck running it is a similar story... brakes easily fall to floor second pump is better but still not great... They don't seem to pump up as much when the booster is working..

I'm just out of Ideas... He's what i've looked at... I've checked all my lines and connections... NO leaks.. I have adjusted my rear shoes out to the point where they are dragging.. I don't seem to have any bad bearings causing play.. I even bought one of the fancy vacuum bleeders that you hook an air compressor too and sucked another 2 quarts through the system... still no better.. My front brake pads are in good shape.. and my rear shoes are probably 25% left, they could be changed, but I don't feel like that is the issue..

I feel like it must still be air... but I don't have any other Ideas on what else to do.

Any advice, ideas, or life experience stories would be highly appreciated...

Thank you all..

Branden Lawson

I forgot to mention... The truck is an 86... so no ABS or anything.
Thanks

coryc85

What about the soft lines? Did you replace them also? Not sure that I have ever experienced this, but theoretically the first push could expand the soft lines from a "relaxed" state and the second push maybe gives you some more pressure. If they are original rubber, I'd change them for peace of mind. Also, most people on here are not fans of autozone hydraulics. In a pinch, I understand, but if you can plan ahead it's much better to buy the Aisin. Is the LSPV still there but rod pulled all the way up or did you actually remove it entirely?

RAD4Runner

If you're already having a hard time troubleshooting a stock system, adding another variable will not help.
How about the other brake cylinder? Inspect both rear cylinders to make sure they are both good, Yes, especially the old one.

akwheeler

Not very likely, but something you could check, if anyone in the past has adjusted the parking brake when they actually should have adjusted the rear shoes you sometimes get some funny things happening. Try slacking off the parking brake cable, adjust the rear shoes then readjust the cable. I think it is more likely you have a hose ballooning though.

Branden Lawson

Rubber lines I haven't replaced.. to check for ballooning is it as simple as having someone push the brake pedal and inspecting the hose as they do it? Also the LSPV is gone completey I have a hard line from the the front to the back screwed into the soft line.

Branden Lawson

Well, My thought process was.. it was definitely the leaky line, and I hear everyone complain about the LSPV, so I thought while I'm at it... I had inspecting the other wheel cylinder on my to do. I will do that and let everyone know.

Thanks

Branden Lawson

Actually, I have adjusted the parking brake in the past, when I first got it, because it wouldn't hold you.... This is something I would have never considered.. Thanks for the Idea.

wallytoo

iTrader: (1)

muddpigg

iTrader: (1)

Since you did the LSPV delete and added a manual proportionate valve, what did you do with the T-junction that returns from stock LSPV to the front brake circuit? Seems like if you left it you would notice a big pool of brake fluid but I'm curious.

I used the multiple pump and hold method for bleeding for quite a while and even a vacuum pump with less than great results. Now after a friend recommended a single pump and hold is my preferred brake bleeding method.

I don't like soft lines. But yes have someone press brakes as you inspect each soft line. FSM says to use a mirror so you can see all sides of line under pressure.

wallytoo

iTrader: (1)

Branden Lawson

The original T is not In use anymore.. I took the line that runs out of the T under the master cylinder and hooked it directly to the soft line on passenger side..

muddpigg

iTrader: (1)

Can you post a pic? Would like to see how you did it. I replaced the T junction with an L junction off a 2wd yota. Just cut T junction off bracket and welded L junction into its spot.

The T block I'm referring to is mounted to frame just across from starter on 22RE.

Branden Lawson

Yeah when I get out there today I'll take a picture.. But I had a T block and an L block.. The T block looked like it had a line from the master cylinder running in the top.. Which came off the T under the master cylinder.. So I unhooked it from the T on the frame.. And hooked it directly to the soft line on the passenger side.. And since I no longer have a return line it made that T unnecessary.. (obviously this could be wrong because I still don't have good brakes)

muddpigg

iTrader: (1)

The L block is for the "to" rear brakes and the T block is MC and return from LSPV to front passenger. Mine had all hard lines coming and going to T block. When I SAS'd, used mount brackets from IFS to hold flex lines to frame and give most amount of travel clearance front axle.

Branden Lawson

Ok guys, so here is how today went. I loosened my Ebrake all the way up and was able to adjust my shoes out some more. I then bled some more as I had help today.. Well I noticed a small stream of brake fluid coming out from behind my "NEW" autozone master cylinder... So I took it out and took it back and exchanged it for another "New" MC. Then I drove across town and picked up another wheel cylinder. (just for good measure, since i had recently changed one. I am also to the point where i don't know that i will buy duralast parts anymore) anyways... I changed the other wheel cylinder, bench bled the new MC and installed it... (one thing i did notice when comparing the new MC to the old AISIN is that the bore where the brake rod goes in was actually deeper than the AISIN) I re-bled everything, then I had a good pedal but it was still lower than I thought it should be once I started it and the booster kicked in.. so I loosened the nut on the brake rod and twisted it out about 2 turns... and now I feel like everything is pretty good!

When the truck isn't running on the first pump I have about 1/4 of the way travel... and while running I have about 1/2 pedal travel... I took it out side and did a few "emergency braking" sequences and the truck will about put you through the windshield. So for the time being I am going to let it ride and keep mental notes and keep an eye on all my lines and brake level to make sure everything is actually ok.

Thanks for everyones help and Ideas. Now I have to figure out what to do about my rusted leaking fuel lines coming out of the tank... anybody else have like million times the value of the truck in labor time. haha

akwheeler

You are spot on with the value of the truck verses the value of labor, with all the time and money I have dumped into my 4runner there is no way I could ever break even if I sold it. I have had several people ask if I would consider selling and I told them all "I doubt you would never agree to a price that would make me want to sell". I was going to tell one guy "you don't have enough money" but I have run into some poor looking folks that actually had lots of money. Glad to hear you have good pedal now.

Branden Lawson

I actually was trying to sell mine awhile back. I bought mine 11 years ago when I turned 16 well I've basically been every where in my yote.. I have a camper top on it.. And I use it when we go on hunting trips and it's awesome.. But I soon realized no one would give me enough to buy anything else as cool.. So I kept it and decided to go through everything and try and get another 300k miles out of it. :-)