Breaks

[Showgoer]

Iv been thinking about doing a break swap on the rear of my 89 Comanche. I was looking at taking the rear disc system from a 98 grand Cherokee. What do I need to do and what kind of modification is involved in doing so. Do I need to switch axles to ?

 

 

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[johnj92131]

Use the search function for "BRAKES" and you will find better answers.  Also, check on the DYI forum.  There is an index in the first thread:

 

 

[Smokeyyank]

Axle swap would probably be best unless you have a dana 44. AMC 20 is a solid axle but don't know off the top of my head if you can swap disc on. 8.25 swap and a disc conversion is super doable just need access to a welder to re weld the perches. 

[Showgoer]

Axle swap would probably be best unless you have a dana 44. AMC 20 is a solid axle but don't know off the top of my head if you can swap disc on. 8.25 swap and a disc conversion is super doable just need access to a welder to re weld the perches. 

I guess I should figure out what rear I have. It’s 89 2 wheel drive.


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[Smokeyyank]

One of the MJ gurus might poke in but my guess is the D35 aka boatanchor. Check and see and that will be the best starting point. If you are just looking for better braking and not doing a full on axle swap a WJ/XJ booster is a great upgrade. 

[Pete M]

threads on booster and disk upgrades can be found in the link in my sig.  

[gogmorgo]

I take my breaks at 9:30, 12, and 2:30. Sorry what were we talking about? 

 

Factory axles for '89 were the Dana 35 and Dana 44. The AMC 20 was only available in '86 but has been found on rare occasions swapped under another year (my '91 will have one soon). C8.25's out of an XJs aren't uncommon swaps either. The d35 is by far the most likely, however.

The good news is there are factory Jeep disc applications for both the d35 and d44 under ZJs. On the off chance it's an 8.25 you can get them from a KJ. I can't guarantee that pulling the whole setup at a junkyard will result in perfectly bolt-on solutions, but axle manufacturers generally don't redesign components unless they need to. Buy the calipers at a junkyard but don't run them, it's not worth the risk, but exchange them as cores; don't bother with junkyard pads or rotors, just get new.

Because it could come up, I don't believe there were factory disc applications for the AMC20 but it's unlikely you've got one so no big deal. But I have seen writeups online for disc conversions from other applications.

Check the DIY index for ideas.