Dumb Brake Question

[sierrablue]

No, I did not mean to type "drum"...

So I've bled the brakes a few times on the Jeep since I got it. Braided stainless hoses, so I should be able to make them rock hard, and keep them there. Every time I bleed them, I make them nice and solid, but a few days to a few weeks later, they're always softish again. And I still have the pressure brake switch, which I've found to be a good indicator of whether or not the brakes are well bled. If they are, the lights come on as soon as you start to touch the pedal; if they're not, it takes some travel before the lights come on.

Last time, I decided to go ahead and flush the entire system, and make good and sure I got all the old dirty fluid out. Now the brakes are kind of soft again, and the fluid is dirty again, which, I made good and sure that the fluid was crystal clear when I flushed it.

My suspicion is that there's a lot of junk in the steel hardlines from sitting before I got it, which slowly works its way into the fluid over time. Is there anything I can do to get those lines thoroughly cleaned, without completely replacing the lines? I mean I've tried some gravity bleeding but clearly it didn't get it all out.

It's just irritating is all. I thought I finally had them all rock hard and solid, and wouldn't have to worry about them for awhile, but that's evidently not the case.

Also--I noticed that in the bottom of my master cylinder, the chamber closest to the back of the Jeep is the rear one, and it has two holes in the bottom. The front only has one. Is this right? PO replaced the master cylinder, and it seems backwards to me... Additionally the chambers are the same size, and I have disc brakes up front. But that shouldn't affect the brakes staying bled...

[Yeller]

Are you sure the rears are adjusted correctly? I find with front discs the brake feel is dependent on the rear brake adjustment. Even with properly functioning self adjusters I have to adjust my rear brakes about every 5000 miles, sometimes more often

[sierrablue]

I'm relatively sure that the drums aren't round. Each one has one spot where they each drag when they rotate. But yeah they move a long ways on the rest of the rotation. Maybe that's all it is...I should probably get the drums resurfaced and readjust them.

[Stuka]

If the adjusters are working correctly, they should adjust when you press the brakes semi-firmly while going in reverse. They do not adjust when going forwards. But I agree, it sounds like the excess rear shoe travel is making the pedal have more travel than it should.

[tgreese]

Suggest you make your initial adjustment with this tool:

https://www.amazon.com/GearWrench-3377- ... B0002SQUJ0

Then do the backing-up maneuver to complete rear brake adjustment. The self-adjusters work well if the parts are not worn out and you carry out the reversing maneuver.

I presume you have the original rear brakes.

Suggest you replace everything that's available for the rear brakes: adjusters, cables, pawl, springs. Make sure the adjuster threads are lubricated, and grease the plateaus on the backing plates where the shooes ride. Check that the backing plates are not worn out - if there are grooves in the plateaus, the shoes will not self-adjust. IMO more likely that the drums are not centered on the hub rather than them being out-of round. You can use the above tool to test the drums for warping too.

If the drums are not perfect, I would buy new ones. The 11" Bendix brakes were used on a lot of vehicles (Fords esp.) and the drums are widely available. They aren't cheap like they used to be, but they are widely available now and might be gone if the economy turns down.

[tgreese]

I'd also replace the master cylinder. Again, if this is something the PO did, you don't know the history. Reman cylinders seem to fail often for no reason other than they were rebuilt.

[sierrablue]

Thanks guys; didn't know that about using the self-adjusters in reverse. I'll probably try that and see how it feels.

No question that the drums are centered on the hubs; they clicked into place, and there is no play there. I've got a couple drums on the AMC 20 J10 rear axle; I'll probably just clean those up and see if they're any better.

If I'm going to go through and totally rebuild that whole rear system, wouldn't I be ahead (financially and functionally) to just get this kit, as well as some rotors and calipers? Obv I'd need some more braided hoses too, a new proportioning valve (right? or would the existing valve work? Also what should I be using for a master cylinder in that case?) and the parking brake might be interesting but...
https://davescustomsunlimited.com/wagon ... acket-kit/

Idk this drum stuff is needlessly complicated and frustrating, and now it's not really even cheaper. Maybe I'll just readjust the drums and slowly buy the parts to put that kit together, and then when the drums are worn out I can just bolt on all the new stuff. Seems like just as much work and less money if anything at this point. Or I get all the disc brake stuff and put the drums on that Panel Delivery...

Feel free to correct me if I'm wrong on any of this. I understand how the drums work and all; I'm just not sure I have the patience or the time to keep fiddling with them all the time.

[tgreese]

...AMC 20 J10 rear axle; I'll probably just clean those up and see if they're any better. ...

Won't fit a Dana 44.

Price out the parts you need. And the drums are much easier to use if you want a parking brake. IIRC the Cadillac rear calipers have a mechanical brake, or you could go with an added electric brake. And you'll need a disk-disk master. There are also transfer-case-mounted parking brakes. Kinda think you're both over-estimating the expense and difficulty in the drums, and under-estimating the expense of the rear disk conversion. Suggest you gird your loins and fix the drums. They work well when assembled correctly, the parts are not expensive, and rear brakes don't wear like fronts.

[Stuka]

Disc brakes are great, but the conversion will costs more than rebuilding the drum setup (assuming it needs rebuilding). For disc brakes you will need a prop valve, lines, the mounting kit, rotors, calipers, potentially a new master cylinder depending on the volume of fluid your current one puts out

And then there is the issue of a parking brake that Tim mentions above.

If you want disc, go for it. Just don't do it with the expectation that it will be cheaper than drums.

EDIT: Also, I think that kit may only work for 74-79 and 86.5-91 D44s. I thought the 71-73 had a different retainer plate pattern. But don't quote me on that.

[tgreese]

'74-79 have Delco brakes, not Bendix. Yes they are different. There should be plenty of kits that will replace the Bendix drums, since the CJs used them '72-75 and the Bendix drums are very popular bolt-on upgrades to earlier models.

Realize that the rear brakes don't do very much in terms of braking. When braking, most of the weight transfers to the front wheels, and the rear brakes keep you from spinning out on curves. Predict the disk conversion on the rear won't make an appreciable difference in braking for that vehicle. Seems like a lot of added expense and effort to relieve you of a little brain work to understand the drums.

[sierrablue]

...AMC 20 J10 rear axle; I'll probably just clean those up and see if they're any better. ...

Won't fit a Dana 44.

Price out the parts you need. And the drums are much easier to use if you want a parking brake. IIRC the Cadillac rear calipers have a mechanical brake, or you could go with an added electric brake. And you'll need a disk-disk master. There are also transfer-case-mounted parking brakes. Kinda think you're both over-estimating the expense and difficulty in the drums, and under-estimating the expense of the rear disk conversion. Suggest you gird your loins and fix the drums. They work well when assembled correctly, the parts are not expensive, and rear brakes don't wear like fronts.

They're 11x2", just like the ones on my D44; Idk what would be different about them. Additionally they all use the same backing plates and bearing sets, as well as axle studs and everything. What exactly is different?

Well you were saying get new drums, which are $60 apiece right there. I'm pretty sure my backing plates are fairly worn, which aren't cheap, plus $35+ for new shoes and another $40 or so in springs and such. They're not cheap to work on at all anymore.

Ok so what's wrong with the mechanical/cable parking brake of the Cadillac? I already have a cable setup; what makes that so hard/such a bad option?

[sierrablue]

Uhhhhhh other than the lug pattern, there is nothing different between my rear axle and the one in a '74, and mine's been swapped to 6x5.5, at least from what I can find. It's even a flanged setup rather than a tapered one. This is the first I've seen reference to them being different at all, and I researched the snot out of it when I went into the parts store and they couldn't find a bearing set for a '71, but they had them for a '74. I know the fronts are drums vs. the disc Delco front brakes, but mine's been swapped to the '74 front axle anyway, even if that was relevant to the rear axle. BJ's seems to indicate that the '74-'76 uses a different drum and shoe setup than the '77+, but all I can find that changed was they switched to a bigger spindle in the front, and did the spring changes in the back. Where are you getting this info about the rear axle being different?

Also, once the discs are on there, I should just have to replace the pads and occasionally the rotors, with occasional bleeding. Obv stuff happens and I may need to replace the caliper or lines or whatever, but they're 100% self-adjusting by design, don't drag at all when they're properly adjusted (vs. the slight drag of the drums), and are way less of a PITA to work on. Additionally, it's not that much more expensive than rebuilding the entire brake system as was suggested. Rotors for that kit are cheaper than the drums. There's a little more upfront cost but not a ton, so I don't really see the downside... Now, if I was getting the BJ's kit, yeah that'd be incredibly expensive. Piecing together my own it's looking like under $500.

[sierrablue]

I'm sorry; I'm sure I want the discs to be the answer, but this is the first I'm seeing of this info, at all, so I'm trying to figure out where it's coming from. I understand that drums offer plenty of power for the back, which doesn't need much anyway, but I also know that they're a pain to mess with, and they're certainly not getting cheaper to work on.

I'm just trying to verify the information since so many people say so many different things on this stuff is all.

[tgreese]

Mmm. Not $20 like a decade ago, but not $60. Granted, it adds up ... if you can turn what you have, go that way.
https://www.rockauto.com/en/catalog/jee ... ,drum,1744

The '74 axle has both 6-lug and the brakes are a different manufacturer. Delco, not Bendix. Look at the picture in the book - clearly different. Don't assume - I predict none of it will bolt up. Don't trust the aftermarket seller's listings; look at the parts book if you want to get it right.

Welp, me being an old timer, the drums seem fine for rears. Lots of newer cars had disk fronts and drum rears ... not terrible.

A pain to mess with? Not to me. You are not the first young person to express this opinion. Pretty easy with some simple tools. I'd be happy to help you add drum brakes to your repertoire if I were nearby.

I expect your panel will have ... 11"x2" Bendix brakes. Not much of an upgrade there.

No first-hand experience with the Cadillac calipers. Check the price and availability. I don't even know what parts to look up. IIRC it's one of the few domestic apps that includes a mechanical brake.

[thej10guy]

For the parts recommended for the link sierra provided above, the parts are all available.

It comes to a total of $139.26, plus the $225 dollar conversion stuff, which would be $364.26 along with other odds and ends you would need. If you would need to change the master cylinder it would end up being more obviously, and a proportioning valve if I remember correctly is about $60 so in total it could definitely be kept under $500 for up front cost.


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[tgreese]

You need rear calipers for an Eldorado, I think.

[sierrablue]

Mmm. Not $20 like a decade ago, but not $60. Granted, it adds up ... if you can turn what you have, go that way.
https://www.rockauto.com/en/catalog/jee ... ,drum,1744

The '74 axle has both 6-lug and the brakes are a different manufacturer. Delco, not Bendix. Look at the picture in the book - clearly different. Don't assume - I predict none of it will bolt up. Don't trust the aftermarket seller's listings; look at the parts book if you want to get it right.

Welp, me being an old timer, the drums seem fine for rears. Seems like a major hassle to figure out some kind of swap to disks when the drums are fine. Keeping drums for the rear was probably was a cost thing ; no need to change to rear disks when the drums work well with the mechanical parking brake. Drums last a long time on the rear. Lots of newer cars had disk fronts and drum rears ... not terrible.

A pain to mess with? Not to me. You are not the first young person to express this opinion. Pretty easy with some simple tools. I'd be happy to help you add drum brakes to your repertoire if I were nearby.

I expect your panel will have ... 11"x2" Bendix brakes. Not much of an upgrade there.

No first-hand experience with the Cadillac calipers. Check the price and availability. I don't even know what parts to look up. IIRC it's one of the few domestic apps that includes a mechanical brake.

I understand how they all work, and I can work on them, but they are a pain vs. pressing the piston in if needed and slipping them around a rotor, and putting 2 bolts in. The springs are annoying and you always get one of them wrong the first time, and you have to hold 12 things at once to start installing new shoes, and you always cut yourself at least once with either the tool or one of the springs when it slips. And then you evidently have to go in and manually adjust them every few weeks/months.

All the '90s Mustangs and such use mechanical parking brakes and they work really well; I actually really like those setups. The ones I don't like are like the ZJ uses, where it has a disc and then the parking brake is like a little drum brake using the inside of the rotor.

[sierrablue]

You need rear calipers for an Eldorado, I think.

Looks like what thej10guy put in to me...

Still needs brake hoses but those should be cheap

[tgreese]

Listing says front left, front right. Maybe I'm not reading it right.

I think you are mistaken about having to adjust them. Only if you don't put them together right. Or they have worn-out parts.

[sierrablue]

Looks like the rears are a chunk more expensive. Still not seeing a huge loss on the discs financially though.