1978 FJ40 Brakes to floor question (search high and low for other posts)

[michaelharrisco]

Okay, I know there are tons of brake post on this forum already and I've read a lot of them already and tried to use the tips, but still have had no luck.

Here is my scenario as best I can describe:
1) purchased 78 FJ40 ~5 months ago
2) few months into ownership, brake fluid would have to be refilled quite a bit for rear brakes.
3) noticed driver side rear cylinder (drums) would show leak.
4) PO already had new cylinders, but never put them on
5) R&R those, bleed brakes, no more leak
6) short time the master cylinder started leaking
7) R&R the master (was actually pretty bummed because CCOT promised an Aisan brand, but upon receiving it was not. I love CCOT, but they let me down this time around and I need to go ahead and install so I put it in.
8) No leaks at all now!
9) Brake pedal seems now to go all the way to the floor from time to time, but with pumps will brake good.
10) Overall, I'm able to drive it and brake okay. I think though the front brakes (disc) are doing all the work.
11) Re-bleed everything again and it seems to have helped a little bit, but still not where it should be.

What gives?

A few theories:
1) I did not bench bleed the master before installing. I thought that once you installed it and bleed lines everything would be fine. Do I necessarily have to remove master and bench bleed? Can I bleed it installed to accomplish same thing?
2) Rear cylinders are not adjusted tight enough so initial pumps are expanding the cylinder then creating the tightness. Can you give me some guidance on how tight to make them? Obviously they can not be so tight that they won't turn by hand, but I still wonder if they need to be a bit tighter.
3) Do I really just need to keep bleeding and bleeding? Each tire was bleed until 2 - 3 pump and bleeds resulted in no air. Is that good enough?

My father in law has been helping greatly on this, but we are running out of thoughts so I thought I'd turn to you guys to help.

Any thoughts?

 

[mydogpea]

When you bled the brakes, Did you start with the wheel farthest away from the master cyclinder and worked your way to the closest?
When adjusting the rear drums, jack up the rear so the tires are off the ground, turn the adjuster wheel until the tires stop when you try to spin them, then turn the adjuster wheel back about 3 clicks. You should be able to feel a very slight resistance but not enough to stop the tires right away.

Hope that helps you a little. Good luck.

 

[Rockets2000]

I think if the MC needed to be bench bled, you would not get any pedal at all. But..........it coudn't hurt. You can do it on the truck if you remove your lines and attach nipples into the ports and rig up some return hoses into the front and rear reservoirs. Pump the brake pedal until no bubbles run through the hoses. Then reattach the lines and bleed per the FSM.

 

[3jvj]

Adjust your rear shoes out.

 

[ingomar]

Good advice here; sometimes it's a bugger to get all the air out. It often takes a lot more fluid than you'd think. Rear shoe adjustment is critical, too.
My '78 had a bad power booster. It had a constant good pedal with the engine off, but felt very inconsistant on the road at times. I couldn't find a booster for this thing, so I ended up adapting a unit I got from "cruiser solutions", I think. That did the trick for me, the brakes feel good. No idea if this is part of your problem, but it may be something to consider.

 

[waiting for time]

Is your master for rear drums? Drum breaks need to keep some pressure in the lines when not applied, disc brakes are pressure free when not in use.

 

[michaelharrisco]

When you bled the brakes, Did you start with the wheel farthest away from the master cyclinder and worked your way to the closest?

Yes

When adjusting the rear drums, jack up the rear so the tires are off the ground, turn the adjuster wheel until the tires stop when you try to spin them, then turn the adjuster wheel back about 3 clicks. You should be able to feel a very slight resistance but not enough to stop the tires right away.

Pretty much did that, but I think I may go back and try to make the adjustment tighter.

Is your master for rear drums?

Yes, classic dual MC (front and rear) from CCOT for this year model. I'm 99% sure it is the right one.

It had a constant good pedal with the engine off, but felt very inconsistant on the road at times. I couldn't find a booster for this thing, so I ended up adapting a unit I got from "cruiser solutions", I think. That did the trick for me, the brakes feel good.

Mine does the same thing described above. Can you post a link to what you ended up installing and let me know cost? I've looked up those boosters before on SOR and the are ~$1K (way out of my budget).



Thanks for all the responses. I think I may try "bench" bleeding the MC while install like suggested, but before doing that may try tightening up the cylinders on the rear. We basically did the tighten until they wouldn't spin anymore then loosen, but I'm wondering if we loosened too much.

 

[michaelharrisco]

Was this your cruiser solution fix?
Dual Diaphram/Reservoir Brake Booster and Master- FJ40 [BT-500] : Cruiser Solutions, custom cruisers, restorations, genuine Toyota parts, body tubs, used Land Cruisers for sale

 

[mydogpea]

I think there's a brake booster off a 79 on ebay right now.

 

[mydogpea]

I'm not for certain on this but I think you net to "set" the brakes after you adjust them by stabbing the pedal very firmly.
Anyone, please correct me if I'm wrong on this.

 

[ingomar]

Michael, that wasn't what I used. This was about 6 months or so ago. What they were selling then was a single-diaphragm unit and you had to adapt (re-drill) the original master cylinder. Mine came factory with a Bendix unit, and I'd rather have kept it original.
I could not find rebuilt units nor anyone to rebuild mine at that time. I'd google it; this stuff is often cyclical and I was told then it'd be available again in time.

 

[Mr. Toad]

#2 question in original post: Did you adjust both cylinders on each rear wheel?

Otherwise, I once received a MC from CCOT which had a smaller bore than what my cruiser was supposed to have. The symptoms were the same as you describe. Do you still have your old one to compare? (Bore size should be cast into the MC somewhere.)

 

[michaelharrisco]

#2 question in original post: Did you adjust both cylinders on each rear wheel?

Yes both

Update: this morning on a cold start...before cranking the pedal was not firm as I stated. It now takes about 1 - 2 pumps before it grabs and I have a good pedal. Even after cranking...same thing. at light / while driving if I pump it 1 - 2 times I get a good pedal. This makes me think I don't have a booster problem like was discussed earlier about when cranking the pedal gets loose.

Would this sound like air and / or the loose cylinders? I'm going to make those adjustments in a week or so and will report back.

 

[ingomar]

Yes, it does sound like loose adjustments and/or air.

 

[Fast Eddy]

Would this sound like air and / or the loose cylinders? I'm going to make those adjustments in a week or so and will report back.

Air will give you soft pedal. Incorrectly adjusted rear drums, or a missing residual valve will cause you to have to pump the system before it engages.

The two problems are not exclusive. You might have to pump it up to feel that the pedal is soft. If it's hard once pumped rolleyes, you just need to adjust and verify the residual valve.

 

[NikP]

I had a similar challenge trying to get pedal. I too didn't bench bleed my MC when I installed it. I eventually went back and used Coolerman's method (see link).

Brake Bleeding 101

I thought I had adjusted the rear drums tight enough but could never get pedal. I finally tightened my rear until the wheel would not turn at all, then I bleed the brakes knowing that the wheel cylinder travel wasn't an issue. This also forces air out rather than it just moving as the wheel cylinder moves. Bleed both axles with the rear drum tight. Once I was done bleeding, then I backed the rear off slightly so the wheel would turn. Did the trick for me.

Sounds like air in your system.

 

[Pin_Head]

As others have said, this problem is most likely due to misadjustment of the drum brakes. There would have to be a lot of air to cause this and they are not hard to bleed properly.

Most people misadjust them because they just tighten them until they hear them drag. This is the wrong way.

You tighten them until you cannot turn the wheel and then back off 3 clicks. This is the right way.

Drum brakes are supposed to make a dragging noise.

 

[stephenDM]

I had the exact problem you are having a few months ago. My brakes were great, but I had to do a periodic bleed. I screwed up and got air in the master cylinder and ended up having a soft pedal that needed double pumping to stop as a result. I thought for sure that it was a symptom of air in the master cylinder or brake lines, and so kept rebleeding. I was positive it could not have been a drum brake adjustment issue since the brakes were adjusted well before I bled the system and I had not touched them.

I reread the helpful posts that say what some of your replies here say -- that double pumping is usually adjustment, spongy brakes are usually air, and was incredulous that my brakes were out of adjustment without my touching them. I went out to adjust them anyways since I knew that would be the first response any post I wrote would get, and it fixed the problem. Although I never touched the star wheels, the brake cylinders in my rear drums were way out of adjustment (my system is front disc / rear drum, so those were the only cylinders to adjust).

I still don't understand how my drum brakes got out of adjustment, but go figure.

I followed the advice that is contained in this post and others about how many clicks to turn the star wheels and letting the brakes drag initially. I also went back and readjusted multiple times over a two week period with intermittent driving around my block and got improvements in the pedal. My brakes pre-date the self-adjusting ones, so I'm not sure if using the brakes in between adjusting sessions was actually helpful or not, but it sure seemed like it was. There's another post here where a guy with spongy / double pump brakes had improved braking after repeatedly adjusting / driving / adjusting / driving. The thread is:

https://forum.ih8mud.com/40-55-series-tech/148772-brake-repair-questions.htmlhttps://forum.ih8mud.com/40-55-series-tech/148772-brake-repair-questions.html

I'm relatively inexperienced, so take everything I say with a grain of salt.

Good luck!

 

[michaelharrisco]

I think I've concluded the drums need to be turned as I'm getting the tight then loss spots. I tighten them up as much as I could. One side was a bit too tight and overheated so I had to loosen it up a bit.

I did a slight bench bleed of the MC on the truck, but not the full blown lines going back into the reservoir. I may try to do that tomorrow.

Still the thing that is bugging me is I still have to pump the brakes. I get one pump all the way to the floor and then the very next pump is nice and tight. Bleed everything again and still feels like air is in there.

I was really hoping tightening the rear cylinders would fix all this, but I'm basically back to where I was except now knowing that I need to turn the drums.

Any thoughts?

 

[Mr. Toad]

Did you check the MC bore?