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post #1 of (permalink) Old 07-23-2003, 07:08 PM
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Rear disk brake conversion – caliper question

I am converting my Scout Dana 44 rear axle to disk brakes - going under my CJ-7. I am using the GM metric style calipers (no parking brake) from a 1985 Monte Carlo. I read that the caliper should be mounted so that the bleeder screw is sticking straight up. But this would place the caliper way down in the 8 o’clock position.

Interestingly most of the kits I have seen (TSM and Warn) locate the caliper up around the 10 o’clock position. While the bleeder screw at this position is still relatively close to the top, it definitely is not pointing straight up.

I would like to know where I should mount these calipers to provide maximum ground clearance and yet still be able to properly bleed them.

By the way, I am fairly certain I have the correct calipers – at least they bolt up fine to the GM metric brackets I bought and look the same as the photos I found on various web conversion write ups.

Has anyone here done this conversion and if so at what position did you locate the calipers and are you having any trouble bleeding them? Thanks for any info. - Tim
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post #2 of (permalink) Old 07-23-2003, 07:23 PM
 
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Re: Rear disk brake conversion – caliper question

Well, you want the bled screw at the very top of the piston (air rises). If you mount it differently, then you will need to remove the caliper and gravity bleed (opening the screw with no brake pressure and let the fluid and air seep out. I helpd the caliper on the rotor so the screw was on top and had my son press the brake pedal to ensure the air was out.
After all that, I rebuilt the axle and positioned the caliper properly and it bleeds just fine. FYI, mine is at the 9 o'clcck pos.

TJ
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post #3 of (permalink) Old 07-23-2003, 09:50 PM
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Re: Rear disk brake conversion – caliper question

Yes I would like to be able to bleed the calipers in place. It would be easier to determine the proper clocking if the bleeder screw stuck out 90 degrees from the caliper body - but instead it sticks out sideways like a snale coming out of it's shell. I wonder in what position this caliper was mounted from the factory on GM vehicles - I have been keeping an eye out for an older Monte Carlo to crawl under and see.

It's strange that both TSM and Warn appear to have their brackets designed to locate the caliper up around 10+ o'oclock - putting the bleeder in a position to potentially trap some air.

With your lower 90 degree caliper placement have you had any issues with the calipers getting fouled with mud or hitting anything? - Tim
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post #4 of (permalink) Old 07-25-2003, 06:26 PM
 
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Re: Rear disk brake conversion – caliper question

The bleed screw doesnt need to be "pointing" straight up, it just needs to be at the highest point to get all the air out.

TJ
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post #5 of (permalink) Old 07-25-2003, 08:31 PM
 
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Re: Rear disk brake conversion – caliper question

What teejay has said is correct, the bleeder dosn`t have to be straight up, just the high point to let out air.
When I did mine I tried switching the calipers from one side to the other to get the best positioning for the
same reason. My brackets and calipers ended up at about the 11 O`clock position.
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post #6 of (permalink) Old 07-25-2003, 08:33 PM
 
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Re: Rear disk brake conversion – caliper question

By the way, TSM brackets are designed to fit in several different orientations. I think they are straight up, 45 deg and 90 deg.

TJ
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post #7 of (permalink) Old 07-25-2003, 08:39 PM
 
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Re: Rear disk brake conversion – caliper question

Whatever position you end up with, it's best to remove the caliper and gravity bleed it while you move it around. By turning it and moving it you will release al the trapped air, then bolt it up and bleed it the normal way.
This is what many of us here have had to do to get all the air out.
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post #8 of (permalink) Old 07-25-2003, 11:58 PM
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Re: Rear disk brake conversion – caliper question

The PO on my `62 CJ5 put 11" not self adjusting drum brakes on my front axle and I've bled and bled the brakes and no difference was notice. I finally decided to upgrade to self adjuster Wagonner brakes. When I took the brakes apart the wheel cylinder and the backing plate was tilted about 30* so the hose would fit. The cylinder always add an air pocket in it. So get it as close to the top as possible.


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post #9 of (permalink) Old 07-26-2003, 03:35 PM
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Re: Rear disk brake conversion – caliper question

My Mom has an 86 Monte Carlo SS. The caliper is rotated up a little. The bleeder screw is at the highest point. I don't know how else to explain it. I can't get a picture because I'm 500 miles away. I'm willing to bet all GM A-bodies had the same caliper though. You'll find that the Monte Carlo's brake hoses are nice and short too (and cheap) with an anti-kink sleeve.

Most of the aftermarket kits put the caliper up high to "protect it." The problem with this is that the higher they go the more potential of tearing off a brake hose because the hose actually starts getting into a bad spot. Where are your front calipers? Does it really matter where your rear caliper is as long as it doesn't hang below the axle tube? Probably not. Besides, unless you run some outlandish wheels the caliper should be protected by the rim and tire.

Any of the 80s calipers will work that take the #52 pad. Trucks, vans, cars, et cetera all work. They come in different orientations, different bleeder positions, different banjo bolt directions, et cetera. They even come with different piston sizes.

If you want to be really goofy you can swap caliper sides and have them on the front of the axle. Kind of retarded in my opinion but people do it.

Anyway, I went to rear discs so I didn't have to pull my drums to hose out the brakes. Every time I came home after playing I'd have to hose out the mud, sticks, grass, and stones. The main reason was so if I broke a C-clip I wouldn't have my tire going AWOL.


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