1974 FJ40 Brake Pull left and drivers side won't stay adjusted.

[middlecalf]

for reference

Yeah, I used the old ramped adjusters, new ones don't have the ramps. Fat side out, no ramp gap.
View attachment 1836088

 

[KWA]

Any thoughts on the 1 wheel cylinder that does not look like the other 3?
Thanks again.

 

[KWA]

for reference

Okay will check. Thanks

 

[KWA]

for reference

Any thoughts on the different wheel cylinder? The picture you attached looks like 3 of the wheel cylinders I have. There is one with no neck or narrowed section. Could that be affecting the brakes, or it is just an aftermarket wheel cylinder?

 

[middlecalf]

I can only really speculate, but if it’s not of the same make/model then it‘s possible that it has a different rate of extension for a given brake pressure as the other cylinders (or to get the same extension as the others it takes a different brake pressure). So that could result in different behavior from the others if they were all baselined the same. That “necking” down possibly indicates that those cylinders have less volume internally and therefore would have a faster rate of extension (but less max pressure), but can only really be assessed by looking at each cylinders bore diameter.

 

[KWA]

I can only really speculate, but if it’s not of the same make/model then it‘s possible that it has a different rate of extension for a given brake pressure as the other cylinders (or to get the same extension as the others it takes a different brake pressure). So that could result in different behavior from the others if they were all baselined the same. That “necking” down possibly indicates that those cylinders have less volume internally and therefore would have a faster rate of extension (but less max pressure), but can only really be assessed by looking at each cylinders bore diameter.

That makes sense. I'm going to take off the rears this week. Maybe the narrow necked one was put on the back wheel? Looks more and more like I probably need to buy a new set. At least for the front.
Thank you

 

[KWA]

Took off rear drums. This is the rear passenger side. Front cylinder has a narrowed neck.

This is the rear drivers side. No narrowed neck. Also both rear wheel cylinders on passenger and drivers side have the adjusting locking metal lever facing inside.

How do I tell where the cylinders belong? I’m guessing the narrow neck cylinder needs to go from the rear passenger to the front passenger.

The rears wheel cylinders that have their adjusting bars facing inward need to moves also. I don’t see any marking on them.

 

[4x4veteran]

I will tell my story, then you can make up your mind.
I have had my 1970 FJ40 since 1973.
Never had much trouble with the drums because I adjusted and inspected them regularly.
The fronts are the hardest to adjust because of the steering linkage.
Being younger this was no big problem.
I have broached the subject of sell the Toy to my wife and she doesn't want to.
I said if we keep the rig then we need to drop some $$$ on the brakes.
As I get older the brakes are becoming more of a pain to maintain.
It cost a couple grand after all was said and done but it is more maintenance free and will be easier to work on should the need ever arise.
Figure in the cost of new cylinders, and disks are not that expensive.

 

[fjwagon]

And there lies the issue, most of us have no clue that brakes shoes all the way around need regular adjustments until the day comes and the brakes are not stopping the vehicle like once did. This shoe braking system works great once you do the required maintenance but it's a lot of leatrning and getting used to or at least that is how it worked for me.

 

[ducktapeguy]

You probably have one of the front wheel cylinders mixed up with the rear. They're different bore sizes, but similar enough that it will interchange. If that happens the brakes will not engage evenly

 

[KWA]

You probably have one of the front wheel cylinders mixed up with the rear. They're different bore sizes, but similar enough that it will interchange. If that happens the brakes will not engage evenly

Yes, it looks like that is the problem.

 

[73FJ40]

My '73 FJ40 has drum brakes all around. the front wheel cylinders are 1 1/4" bore, single acting (one cup seal), actuating the cylinder pushes only one way. The cylinder is larger on one end (1 1/4" bore) and narrow on the other)two on each wheel.

The rear wheel cylinders are 7/8" bore, double acting (two cup seals) two on each wheel. You clearly have a mis-match.

Note that your brake linings are NOT in accordance with the OEM design. If you look for the OEM manual illustration, you will see that the lining placement on the shoe is asymmetrical, and is not as long as the linings in your pictures. Additionally, your retraction spring arrangement does not match the factory design, which has one spring on the inboard and one on the outboard of the shoes in each setting.

 

[73FJ40]

The illustration below points out the asymetrical brake linings and the correct orientation of the retraction springs.:

 

[hobbes]

If it were me, I’d do a 60 series (or mini-truck) knuckle and brake swap on the front end and be done with it.

 

[Grayscale]

Drum brakes stop straight on mine. I have stock(ish) diameter and width tires.

Not long after rebuild, I took the new shoes and removed some gunk that was building up on the shoes. It almost appears that at highway speeds, some leaking oil from your knuckles can coat the drum and build-up on the shoe. Totally easy to fix with a soft wire brush, but, it needs inner axle seals.

In the past I had trouble bleeding, on my '73. The correct amount of unseating the bleeder screw insures that no air enters, and the fluid should drain vertically up into a bleeder bottle to get rid of bubbles in the cylinders.

Sure you can upgrade. But, I wouldn't necessarily expect someone to properly accomplish a disc swap if they can't get thru factory drums and a Haynes manual.

 

[ducktapeguy]

On my drums the pads will only go on one way. One of the notches on the pistons is wider, and the corresponding brake shoe has a wider lip that won't allow it to fully seat when reversed. Also when you're rebuilding the cylinders, make sure the all go back to the proper position on each wheel. Each one is labelled and if they're put back wrong you'll have issues.

A disk brake conversion is a worthwhile upgrade and something I've been meaning to do for a long time, but once you get drums set up properly they work pretty good. It is a lot more hassle and more maintenance for sure, but braking power has never been an issue. When I bleed the brakes I found it's easier to unscrew all the adjusters equally until the wheel locks up, then bleed each cylinder, then back off the adjusters to give the proper clearance. If even one of the pistons has too much clearance you'll have a hard time getting the brakes to bleed properly.

 

[hobbes]

When the stars align, and they're dry, drums brakes stop as good as disks. It's just a matter of how often you want to try to align the stars.

 

[KWA]

The illustration below points out the asymetrical brake linings and the correct orientation of the retraction springs.:
View attachment 3162569

I saw a similar picture before but never notice the brake lining.

 

[KWA]

If it were me, I’d do a 60 series (or mini-truck) knuckle and brake swap on the front end and be done with it.

Hopefully one day. Just trying to get it on the road for now.

 

[KWA]

Took the brake cylinders off. A few of the pistons where stuck. I assume from sitting. Bores looks decent. Looking at coolermans site on how to rebuild the cylinders. Can't find any rebuild kits locally. Any good source for those online?