1984 fj60 brake frustration

[rawrt]

Replaced the master with Aisin since the original was stuck from sitting. New booster due to a leak. New calipers. New wheel cylinders.
I have the rears bled after a bench bleeding but nothing on the fronts. I can’t cycle the pedal more than a few inches without it feeling like I’m hitting something. Tried gravity bleeding, speed bleeders, and trusted 2 man pump deal.
I had the proportional valve off and blew air through it and both ports were free. Is it stuck and not moving when I bolt everything up?
I don’t know what to try next. Is my new master bad?

 

[DrRock]

Replaced the master with Aisin since the original was stuck from sitting. New booster due to a leak. New calipers. New wheel cylinders.
I have the rears bled after a bench bleeding but nothing on the fronts. I can’t cycle the pedal more than a few inches without it feeling like I’m hitting something. Tried gravity bleeding, speed bleeders, and trusted 2 man pump deal.
I had the proportional valve off and blew air through it and both ports were free. Is it stuck and not moving when I bolt everything up?
I don’t know what to try next. Is my new master bad?

Interesting as my truck is exhibiting similar issues and drew the same conclusion as you stated. Procedure wise, I did exactly what you described above. I do get fluid to the front calipers using the gravity method but still have wicked spongy brakes. I've noticed that a couple test drives the fluid level in the reservoir is going down too so I've topped it off and completed more vacuum bleeding on all four corners. There is no evidence of fluid leaks anywhere. I am wondering too if I have a bad master cylinder. I'll be checking mine on Wednesday to see if it is leaking into the new booster and will report back.

 

[4runner2FJ60]

Did you follow the FSM procedure and wheel order bleeding? Did you adjust the new brake booster pushrod pin depth properly? Lots of variables. What about your 40 year old soft brake lines? I've replaced all the above and went from no brakes to actually really good brakes. Sounds like maybe the bleeder screw is not loose enough on the fronts when pressing pedal?

 

[rawrt]

did the rod length incorporating the nylon spacer it came with.
Adjusted the rears with a little drag and started bleeding the rear driver then the rear passenger. Closed up everything and the pedal feels like I hit a wall. No fluid at the fronts

 

[4runner2FJ60]

Where is the spacer? Where did you get the booster? I did not use a spacer on mine. Just to be clear, you adjusted the pin at the front of the booster to match your old booster setup? Almost sounds like something stuck in the lines or like you said the proportioning valve if we can call it that.

 

[rawrt]

Also did the math for the stick out of the booster into the master

 

[diesellibrarian]

X2 on the soft lines failing. They can swell and close up. An easy way to test is to disconnect the soft line where it joins the hard line, and see if fluid starts to flow.

I am also curious about this spacer. I know some boosters require a spacer if being retrofitted into an earlier truck (like an FJ40), but I've never heard of a spacer being used on a 60 series. I think that spacer might be preventing you from getting the necessary travel out of the master cylinder plunger.

 

[rawrt]

Running out of travel with the spacer?
How does one test the proportional valve? I hate to spend $100+ on one if I don’t need it.
The master was completely seized after sitting nearly 20 years.

 

[rawrt]

I should add I had a normal pedal distance when I was pumping while bleeding the rears.

 

[4runner2FJ60]

I'd look at those soft lines unless you know they are brand new. The one that drops to the T on the axle and both at each wheel. The 62 is where the proper "proportioning valve" started. Ours are more of a three way valve, not much to it.

 

[diesellibrarian]

Running out of travel with the spacer?
How does one test the proportional valve? I hate to spend $100+ on one if I don’t need it.
The master was completely seized after sitting nearly 20 years.

Yes, if there’s a spacer between the firewall and the booster, it moves the master cylinder out from its expected position (assuming the old and new boosters are the same size), and the push rod will be too short to push the pistons the length of their full throw, which may mean you’re not creating much hydraulic pressure in the front brake circuit.

 

[Thechief86]

Aside from several parts failing in my brake system, the bleeders in my rebuilt but original calipers were clogged up, and I didn't realize until I fully removed them and cleared them out with a piece of welding wire. Once I could get fluid through the bleeders, and properly adjusted the pushrod at the pedal, as well as the rear brake adjusters, and bled in the right order, my brakes have been peachy and do a respectable job of slowing down my heavy wagon.
I'd pull the bleeders from the calipers and make sure they're clear, and maybe even leave them out overnight to let fluid flow all the way down, then try again in the morning with a buddy at the pedal.
One trick I do is to open the bleeder, have my buddy push the pedal all the way down, then close it before letting the pedal back up. I do this several times to establish fluid at the bleeders, then go around again with the pump up and then open method. It usually works really well. If you got Aisin parts, the odds are good that your parts are fine and will be for a long time.

 

[rawrt]

I've left the bleeder out of the calipers overnight and still get nothing. I disconnected the hard line leading to the short rubber line in the front leading to the rubber line and still don't get fluid coming out.

 

[Thechief86]

Did you bench bleed the master cylinder before hooking up the steel lines?

 

[rawrt]

I bench bled it and worked the bubbles out. The farthest part from the reservoir had air but I didn't see actually fluid coming out. I used a syringe to shoot fluid into the line and watched bubbles move out of the clear plastic elbow.
The line closest to the reservoir push fluid.
I'm guessing both lines should have been pushing fluid the same amount?

I had some rust chunks floating around. Did they ruin my new master cylinder?

 

[Thechief86]

Rust chunks can definitely cause seal issue, but yes, it should have pushed fluid from both outlets when bench bleeding. From here, I'd open that line at the master and have a friend push and hold the pedal down until you get it right again, and do that several times until you have strong fluid leakage around the nut. Then start over with your bleeding process.

 

[rawrt]

I'm using a scrap pieces of 3/16 solid line so I cant see what's moving like a could if I had a clear tube. The MC didn't come with anything for bleeding it.

I'm not letting this thing beat me

 

[rawrt]

Used a clear line to verify the port farthest from the reservoir was actually moving fluid. No luck. I have another on order from Aisin's online "jungle" website. It might be here Friday. This one will be returned.
I see why they sell kits with CLEAR line.

 

[DrRock]

Are you using the City Racer Brake booster? If so, the spacer is not needed for a 60. I pulled the spacer out today and checked the master cylinder and have no leaks. My truck has been sitting for a while and I just got it back on the road. When I got home today I noticed the fluid in the reservoir was down a bit. Traced it to the passenger side rear piston which must have started leaking a short while ago. Replaced it and the brakes feel much better now. Hopefully your issue is resolved with a new master cylinder.

 

[rawrt]

Ill definitely be looking at that spacer I put in. The new booster looked smaller than the old Bendix brand that was on there. The old junker is still sitting on the bench.