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subzali
06-14-2006, 09:38 PM
:rant:

Brakes don't behave ANY differently than before.:rant: I got a NEW OEM AISIN master cylinder from Burt this afternoon, bench bled it, installed it, bled the brakes, and gave it a try.

Pedal travels fairly far on the first pump (6-8 inches), and stops the truck pretty fast when moving. Second pump travels less, harder to stop the truck (feels more like braking with the engine off), third travels less etc.:rant: (basically it is pumping up)

Engine idle gets jumpy and idles down slightly when pumping the brakes at idle just sitting in place. Pedal swooshes somewhat like before.:rant:

We think there's still a little air in the lines, but not much because the pedal isn't squishy, once it gets hard it's hard.

Questions:
1) Does it sound like the booster I yanked off of the FJ60 is also a bad one?
2) If the booster is bad, is there still a danger (as I guess there was before) of running 5 and 6 cylinders lean and burning stuff?
3) Cany somebody or everybody with an FJ40/55 describe what their brakes do? Or confirm if they observe the same behavior from their brakes?
4) Did I miss something in the bleeding procedure?
5) I had to cut the rod on the new booster, does it sound like I may be having a conflict with that?
6) Any other ideas? Wheel cylinders seem to be fine, no leakage or anything...:rant: help:(

Shark Bait
06-14-2006, 11:32 PM
Probably try bleeding the system again. Have you adjusted the rears?

subzali
06-15-2006, 06:04 AM
Ooh, good idea :thumb:

I was planning on bleeding the system again anyway, but I've never adjusted the rears so I should probably do that.

A couple other things I thought of: is it possible that the check valve could be clogged or something? Or the hose that runs from the booster to the engine is clogged? I'll play with the pedal travel and pumping up, but I'm really concerned about the engine idle changing while I'm pumping the brakes, I think that has something to do with the booster.

Rzeppa
06-15-2006, 10:10 AM
Engine idle gets jumpy and idles down slightly when pumping the brakes at idle just sitting in place. Pedal swooshes somewhat like before.

We think there's still a little air in the lines, but not much because the pedal isn't squishy, once it gets hard it's hard.

Questions:
1) Does it sound like the booster I yanked off of the FJ60 is also a bad one?
2) If the booster is bad, is there still a danger (as I guess there was before) of running 5 and 6 cylinders lean and burning stuff?
3) Cany somebody or everybody with an FJ40/55 describe what their brakes do? Or confirm if they observe the same behavior from their brakes?
4) Did I miss something in the bleeding procedure?
5) I had to cut the rod on the new booster, does it sound like I may be having a conflict with that?
6) Any other ideas? Wheel cylinders seem to be fine, no leakage or anything...Answers:
1) Yes, or a cracked/leaky check valve. Most likely the booster though, if the check valve were cracked and leaking you'd have a vacuum leak all the time, not just when you press the brake pedal.
2) Yes. Been there done that, burned #5 exhaust. Head job=$$$
3) I press on my brakes, I slow or stop, depending on how hard I press. I do not experience any change in idle. Change in how the engine runs when you press down on the brakes is a sure sign of a vacuum leak at the booster.
4) Probably not. Your description does not sound like you need any additional bleeding.
5) No, you usually have to adjust the rod length whenever a new master is installed.
6) Yes, adjust your rear cylinders. Having braking at a higher pedal position on the 2nd or subsequent pumps is always a sign that the cylinders need some adjustment.

Rzeppa
06-15-2006, 10:18 AM
I was planning on bleeding the system again anyway, but I've never adjusted the rears so I should probably do that.

A couple other things I thought of: is it possible that the check valve could be clogged or something? Or the hose that runs from the booster to the engine is clogged? I'll play with the pedal travel and pumping up, but I'm really concerned about the engine idle changing while I'm pumping the brakes, I think that has something to do with the booster.Your description does not fit with air in the lines. Air in the system makes for soft pedal.

A clogged check valve or vacuum hose would mean that your booster would not operate. You probably already know the procedure to test if the booster is operating, but to reiterate: Engine off for at least several minutes so there is no residual vacuum for the booster. Press brake pedal until it stops at some point. Maintain same, even pressure with foot on pedal, then start engine. Pedal should now travel down some with the same, even amount of pressure with your foot on it.

A change in how the engine runs when you press the brake pedal is almost always a vacuum leak in the booster. They can be rebuilt and kits are available. I haven't done it (yet), but there is a rebuild procedure in the manual.

mhdsummers
06-15-2006, 10:29 AM
What Jeff said. My guess is your booster too. I will only add that I noticed a very slight change in idle speed when my cruiser was a two or three pumper and my booster does not leak AFAIK. After I replaced the master cylinder, adjusted, and bleed, I no longer notice the change in idle. Buy one of those vacuum pump dealies and test your booster. It should hold a vacuum. Also, I dont think the line from the booster to the intake manifold could be clogged since there should be nothing in your intake to clog it but you might as well check.

subzali
06-15-2006, 09:35 PM
I tried the testing procedure last night and everything checked out okay, just like it was supposed to. I still get the idle change when pumping though, so I think I'm either going to get a new booster or get the vacuum dealy and check it out, if it's not too expensive. Adjusted one of my rear drums tonight, it seems like that made a difference.

Jeff - I read your writeup and you say there are 8 places to bleed the brakes and 8 places to adjust the wheel cylinders. I only found one place on each of the rear drums to bleed the brakes, which would mean if you have four wheel drums you'd only have 4 places total to bleed your brakes. Maybe I'm missing something?

When I tried to adjust the shoes out, only one of the four adjusters would turn. All the others were...(jammed, stuck, all the way extended,...:confused:)...what does that mean? Do I need to replace wheel cylinders now? Or does that just mean that the shoes are all the way against the drum already? I could BARELY hear dragging on either side (that Lockright is loud compared to brake dragging :D)...so any thoughts there? Thanks again guys, I'm getting it figured out...

Shark Bait
06-15-2006, 09:46 PM
Matt,

It's likely your wheel cylinders are frozen. Rusted and won't move. You could try pulling the drum off and going at it from the front. Ultimately, you'll want to either repalce or rebuild the wheel cylinders. If you have the money, an alternative is to install rear disc brakes. TSM in Castle Rock makes a nice kit. Complete it's around $500 including loaded GM calipers. Rebuilding the cylinders is a PITA, but probably the cheapest way to go. If you have one that's really bad you'll have to replace it. You probably won't know until you have it apart. When you're in there you might want to replace the brake shoes. That's why it's worth considering the disc conversion. Jeff will probably pipe in and say he thinks drums stop better. Discs aren't bothered by being wet like drums are. Once you've converted to discs it's less maintenance because there is no adjusting involved.

HTH

Hulk
06-15-2006, 11:28 PM
Matt,

Earlier all-drum brake 40s had two wheel cylinders per wheel -- that's what I had on my old '75. The later models had only one wheel cylinder per drum. They probably started this in '76, when the 40s went to discs up front.

So 4 places to bleed and adjust is correct for your model year.

/we have three Matts in this club. Maybe more.

mhdsummers
06-16-2006, 12:18 AM
I have a number of wheel cylinder rebuild kits. Not sure how many. If you are interested email me at mhdsummers@hotmail.com.
I will be going through Golden tomorrow at 9am and then again in the late afternoon.

Rzeppa
06-16-2006, 12:05 PM
I agree with Chris that (1) You've got stuck adjusters. I had one recently that I was able to un-stick by taking the drum off, spraying liquid wrench on the threads of the adjuster, then working it with vice grips on the adjuster; (2) Replace or rebuild is even better; (3) disks are great in that (a) you don't have to deal with adjusting and (b) if you break a rear axle it won't walk out on you.

BTW, disk calipers can stick too. BTDT. Disks can fade with heat, BTDT also. And drums can be quickly dried by riding on them lightly just after your water crossing, works fine unless there's a huge hill climb on the other side of the creek. IMHO the biggest downside to disks is initial cost, they're a major chunk of change!

Matt, I did not mention in my article that some cruiser drum setups have one bleeder per wheel, yet still have two cyliders. Both cylinders are bled from a single bleeder port. My 71 has a port on each cylinder, but my 78 FJ45 has only one, even though it has two cylinders per wheel. I can't remember which setup my 76 has, it's been a while. I do know my 76 has two cylinders per wheel though. You can see the photos on my resto pages. The single cylinder per wheel setup was not introduced until 1980 when the parking brake was moved to the rear wheels with the introduction of the split case.

In any case, it sounds like your biggest issue is a leaky booster. To give you a frame of reference, I drove mine with a leaky booster for a year or two before I burned up my valve, so it's not an instant death thing. I was still able to drive home on 5 cylinders, but the little pieces of valve sound like hell rattling around in the combustion chamber! It cleaned up the carbon really well though :-/

subzali
06-16-2006, 05:45 PM
Okay guys, thanks for the help as always :thumb: One of things I love about this club is the wealth of knowledge and the willingness to share experiences, even the bad ones :o. Right now disc brakes are not enough of a priority for me to drop $$ on, once I get these drums figured out they'll work pretty good for my truck for now, heck even now (with or without sticking cylinders etc.) the truck brakes fine, I can lock up the tires at 50 (maybe not the MT/Rs, hope I don't have to find out on that one).

Only problem with the booster is that my dad and I disagree on how long it's been acting like this. I think it's been like this since we owned it (1.5 years), and before that who knows? My dad thinks it developed since we owned it, but neither of us can really pin down an approximate time. Well Sunday should be the last time I have to drive it on a bad booster, Monday I think I'm going to go get a different one that hopefully works. I'll have whoever's on the run check it out one last time for me though :D

subzali
06-19-2006, 11:33 PM
Well I went to the Yota Yard and exchanged for a different booster today. It doesn't really feel much different than the other one, so I don't know? The guy at the yard was saying that these things don't go bad too often, so if two feel pretty much the same I'm having a hard time believing they're both dead?

Anyway, idle doesn't change or anything on first press of pedal, but if you pump it two or three times and hold it then the idle gets rough. My two shoes on the bottom of the drums are still frozen, we got some liquid wrench on them today, I think they're going to take a while. But I think my current pedal travel, which is considerable, is from those two shoes not being adjusted closer to the drum and taking a fair amount of brake fluid to make contact. I think once I get them adjusted it's going to be sweet! The truck already stops quick with one press of the pedal, and the booster is definitely doing something because I don't have to push too hard, so now I don't have to try and run red lights for fear of not being able to make a quick safe stop :D