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| 9" brake drums on a Jeep 8.25? https://slantsix.org/forum/viewtopic.php?t=54600 |
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| Author: | SpaceFrank [ Wed Feb 12, 2014 5:40 pm ] |
| Post subject: | 9" brake drums on a Jeep 8.25? |
So I pulled an 8.25 axle out of a mid-80s XJ Cherokee to swap into my A-body. I want to order all new brake hardware, and Rockauto is telling me the only options are for 10" drums, either 1-7/8" wide or 2-1/2" wide. Unfortunately, this axle has 9 x 2.5" brake shoes on it. I didn't know the 8.25 axle ever came with 9" drums. Any ideas on what brake hardware I should be looking for? I'll be asking on the Jeep Forums as well, but I figured I'd also check here. Unfortunately I don't have the old drums, so I can't check for part numbers. The axle in the junkyard was already missing one brake drum, so I took the other one off so I didn't have to pay for it... regretting that decision now. I do remember the drum having shallow fins on it. The bolt pattern is 5 x 4.5". Does anyone know what other cars would have used this axle with 9" drums, and if they would be interchangeable? The gears inside look really good, and the fluid was pretty clean with no metal shavings, so I'm wondering if it was either rebuilt fairly recently or swapped in from a newer vehicle. Before anyone asks, I'm sure it is an 8.25 axle. It has the pentastar logo next to the casting number, which is 4384213. Above that is the number 4060, a capital letter I inside a triangle with cut off corners (or an irregular hexagon... your choice), and a large number 3. There is no axle tag; I had to verify the ratio manually. The axle width at the outsides of the brake backing plates is right at 54". It's difficult to measure by myself, but the hub to hub width looks like 60-3/8". Could be 60-1/2"; I have to eyeball the offset from backing plate to hub. So it's probably around 61.5" with drums on. |
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| Author: | Joshie225 [ Wed Feb 12, 2014 6:24 pm ] |
| Post subject: | |
There were Dakotas with the 7 1/4 and 9" brakes so you might try looking up an early 5-lug Dakota. |
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| Author: | WagonsRcool [ Thu Feb 13, 2014 10:15 am ] |
| Post subject: | |
I wonder if you have an early 90's Jeep donor. AFAIK Jeep was still AMC- Renault in the 80's, while I recall a quite a few that Torque-flite trannies, I don't recall seeing Mopar axles in them. |
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| Author: | DusterIdiot [ Thu Feb 13, 2014 3:06 pm ] |
| Post subject: | Lol... |
Quote: I wonder if you have an early 90's Jeep donor.
No it'd be an 80's, I had a 92 Laredo 4.0L HO and the rear drums were 10", my buddy with the 1989 Laredo 4.0L had 10" rear drums.... I'd bet the 4 cylinder vehicles in the mid-80's were 'downgraded'...
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| Author: | SpaceFrank [ Thu Feb 13, 2014 4:36 pm ] |
| Post subject: | |
The donor vehicle was a 1984 Jeep Wagoneer, which in those years was essentially a Cherokee. I didn't even bother to check the engine the donor had, but DI is probably right about it being a 4-cylinder. Josh's suggestion was great. I pulled one of the brake shoes from the axle, and it matched up to the pads recommended for the first year Dodge Dakota, I think 1987. It sounds like RockAuto's database just doesn't realize some of these XJ bodies came with 9" brakes. I sure didn't know. The only other question I have is what the hell is up with the brake fitting pictured below. There was a rubber hose on that nipple before. I have no idea where it went on the car. The nipple appears to feed into the axle tube, not the brake line. I was thinking remote differential fill, but it's way too small to be practical for that.  Speaking of filling the differential, this housing has a rubber cap on the cover instead of a metal plug. That's mildly irritating. May have to borrow another 8.25 cover in the future. |
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| Author: | sandy in BC [ Thu Feb 13, 2014 5:21 pm ] |
| Post subject: | |
The nipple you refer to is the axle vent. Attach a hose....run it up into the trunk or add a lil plastic vent fitting. On my mud bogger I had a funnel that fit the vent hose and would add fluid through it. |
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| Author: | Danarchy [ Thu Feb 13, 2014 6:20 pm ] |
| Post subject: | |
I understand the 8 1/4 gives you the 5 x 4.5" bolt pattern, what kind of ratio does it have? and why not just use a LBP 7 1/4? |
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| Author: | DusterIdiot [ Thu Feb 13, 2014 8:36 pm ] |
| Post subject: | The race rules... |
Quote: I understand the 8 1/4 gives you the 5 x 4.5" bolt pattern, what kind of ratio does it have? and why not just use a LBP 7 1/4?
He has a race rule limitation on how much he can spend on parts for the car in a season, I think from previous threads...I know on the later Jeeps (90's)...typically the Wranglers with 4 cylinders got 3.55 and 3.91's in the rear while the 6 cylinder vehicles got the less fun ratios...-D.Idiot |
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| Author: | SpaceFrank [ Fri Feb 14, 2014 8:52 pm ] |
| Post subject: | |
According to the letter of the law, yes, you're budget-limited in the 24 Hours of LeMons. To be honest, though, they don't really care how much we spend on this car. You get a lot more leeway in LeMons with a 225-powered '64 Dart than you do with a Miata or an RX-7. The judges know how slow we are. The main reason I went with the Jeep axle was to get a decent ratio easily; they're all over the local junkyards and they're basically all 3.55:1. I don't trust myself or my teammates to do a gear swap properly, so it was better to find a complete package to swap in. Upgrading to a stouter rear end was a secondary benefit. The 7.25 is plenty strong for the 140ish HP we probably have now, but there are vague future plans for forced induction... I'll have to weld on new spring perches, but that's not a big deal. We're going to bolt everything up before I even tack them on, just to make sure we get the pinion angle right. It's also considerably wider, but only about an inch more than an F-body axle. We're already running high-offset wheels to deal with the bolt pattern adapters we had on the SBP 7.25 rear, so I'm hoping everything will fit as-is. If not, I'll have to break out the heat gun and baseball bat for some ghetto-fabulous fender rolling. I wouldn't have been okay with this a year ago, but considering how much body damage we accrued in our first year of racing, I'm less reticent to abuse the sheet metal now. 
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| Author: | Danarchy [ Sat Feb 15, 2014 6:30 am ] |
| Post subject: | |
Quote: ghetto-fabulous fender rolling. OUCH! I feel bad when I pull parts at the salvage yard.  I look forward to following your progress. |
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