[sandcruiser]

Hey all
the drums in the rear are killing me. Slowly, but surely. I've now had 3 different mechanics (along with myself) "repair" them a total of 5 times...
but they still can't seem to stop the rear tires evenly.

It seems like the problem is related to the ebrake, but I'm not sure how.

Basically, if adjusted correctly (tighten until hard to turn wheel, back off slightly) they brakes work just GREAT for about an hour.

Then, they just keep getting tighter and tighter. Or they don't really work at all.

I'm at a loss, here.

I've checked the bellcrank thingy and it moves freely. The cable slides fine. Nothing seems amiss besides maybe the little cable that connects the bottom of the shoes-- it runs through a little bit that swings side to side. On one side, that little bit was all stuck. "Aha!" I thought. "The Culprit!" But now I've fixed those and they swing freely.

The small cables are pretty worn and look like they had little metal rings on them that fit into the swingy part... those rings now move along the cable. Could this finally be the real problem? I sure hope so.

I've spent the last two hours reading up on disc brake conversions, but I'm reluctant to use chevy parts down in Central America (this really is Toyota Territory, no cadillacs here) and also reluctant to try to fab up a system for an Isuzu as this is my daily driver.... the $500 or so price tag on doing the rear discs is also a bummer if I can get these darn drums to work! I don't even need high-performance braking, I drive slow! I just need both rear wheels to slow down at pretty-close to the same time. Last road worthiness test showed more than 50% difference.

In short: What are all the reasons that the rear brakes would act differentely/not release?
Keep in mind, the fronts are within 2% of each other and work just dandy. Unless the backs get really really tight, then the brake pedal gets pretty firm.

Thanks!

[sandcruiser]

Oh, I should also include that the wheel cylinders are less than 3 months old, Toyota OEM parts (expensive suns of guns).
The drums are a little out of spec, but the mechanic had custom rebuilt shoes made that are slightly thicker, to match the drums (about 1mm beyond "max" size)
I doubt that the oversize pads are the culprit, but I'm looking for used drums .... new ones would cost me about the same as a RDB kit!
The master is also about 3 months old, ie: New.

[Dynosoar]

Have you tried to disconnect the self adjuster. All you have to do is bend the self adjusting arm away from the adjuster (star) wheel. It's worth a shot.

Dynosoar

[60wag]

I had an issue some years ago where one side (drivers side?) would continue to self adjust until the shoes were always rubbing and generating some serious heat. If I didn't use the parking brake it was ok. But I can't have something as important as the parking break not working so I dug into it. I couldn't find anything wrong. Both sides were properly assembled. Both drums were technically in spec but when I swapped the drums, the problem disappeared. Maybe something else in the system had worn to the point that the drum inside diameter was allowing the adjuster mech to continue over adjusting the thing? If you haven't tried it yet, put a NEW drum on the side with the problem. HTHs

[S&S1stCruzer]

I did my rear brakes about 2 months ago,
NEW OEM wheel cylinders, New OEM brake shoes, NEW cable with metal rings - Yes rings are important. They move a part of the mechanism with the parking brake I believe. I think the biggest thing people do on this board when it comes to adjusting the rear brakes, is using that tighten the star method until the brakes don't turn and then back off. The rear brakes ARE self adjusting. When you pull the ebrake hand it will spin the star wheel (you will hear it click) it took a few minutes but you keep pulling and releasing until you stop hearing it click and bam your brakes are adjusted. I also replaced my master cylinder in this process. Hope this helps some.

[sandcruiser]

I think I'll try to disable the adjuster....
and see if I can get some new short cables w/ rings.
And move forward with the Isuzu RDB project.

Something is bound to work!

[sandcruiser]

newest thought: since this rig WAS a 4wheel drum, I'm guessing that many of them are 4wheel drum here... so maybe the replacement Master cylinder has some sort of residual valving in it?? Which, combined with my residual valve from the fj60 donor, could be too many valves?

I may tear into the master to confirm.

Anyone know any tricks to minimize bleeding post-master teardown?

[rat]

you're having the same problem as I've had for years ... Landcruisers are famous for bad drum brakes. Apart from the normal hydraulic issues, I've read that the OEM drums distort when torquing wheel nuts on, which pulls them out of round - so having them skimmed doesn't fix the dragging. Also, the OEM rubber brake lines distort under pressure(steel braided lines might help). My self adjusting mechanism never worked well - my shoes would always be dragging - so I removed the self adjusters - adjust manually every few months. I also fitted new OEM drums, new shoes, new springs, re-built wheel cylinders and master...

[sandcruiser]

ok, so after all of that expense..... do your rear brakes WORK now? cuz I'm looking hard at just going to discs...

[Jan-78FJ40]

Is your rear a full floater axle? the drums for that are thicker than for the semi floater, according to toyota specs.
I put turned non full floater drums on a full floater axle and had exactly your problem. went back to the full floater drums, and no problem anymore.

I understand that this does not offer a technical explanation, it is a pure observation.

j

[kadie]

Working on my rear drum brakes is also one of my favorite weekend jobs . But I believe you should first start to get your rear brakes to work fine in normal operation (hydraulic actuated, that is), and then check the operation of your emergency brake (cable actuated). Your braking problem seems to be pressure-related to me; or you build up too much pressure in your back brake hydraulic system (making the brakes tighter and tighter), or you loose pressure (no brakes at all). Considering this, your problem could be located in your master cylinder, as your rear brakes are the first to brake, and once you travel the brake pedal further, your front brakes are then actuated (this for stability reasons). You have mentioned valves somewhere in your messages, so I would suggest that you have indeed a close look at that. In addition, there is a load-sensing device in your back brake hydraulic system, maybe that is worth a look also.

Good luck!

Dieter
'86HJ60

[sandcruiser]

Thanks Dieter. No load-sensing proportioning valve on this truck, just the proportioning valve under the master. What I'm wondering is if maybe the new master had a valve pre-installed (like on a mini truck)
haven't had time to tear into it yet.

But maybe this afternoon I'll try swapping in newer drums and used, but still serviceable shoes... and also check the valve.

With fingers crossed...

[Spike Strip]

Did anyone ever find a fix for this ?? Sandcruiser ???

[alaska60]

This seems to be a popular issue..... I have seen several threads over the past couple weeks with the same problems....maybe a candidate for the FAQ?