Rear Disc Brake Conversion - Junkyard Approach

[AndyA]

I am currently researching this because it is hot and I have to be efficient at the junkyard. Do I have this right and is there anything I have missed?

Note - I want to do this for ease-of-maintenance reasons, I know there is no performance gain.

I can get parts from a 1995-1998 Grand Cherokee or a 2002-? Jeep Liberty. Looking at both vehicles gives me more choice in the junkyard on picking the best ones.

Need to get:

• calipers
• caliper mounting brackets
• four bolts that attach brackets to axle (they are longer than the drum bolts)
• soft brake lines
• bolt that attaches brake line to axle (what is this? any pictures of it?)

I haven't included rotors and pads because I will buy new ones.

Check the calipers work and if not use them for the core return when buying new calipers.

Use a cable clamp to attach the existing parking brake cable to the calipers (don't want to crawl under the junkyard vehicles to remove the matching parking brake cable setup). Which clamp would work best? @Dan_Goodwin mentioned doing this but no pictures or further details.

In this post: https://wranglertjforum.com/threads/tj-rear-disc-brake-conversion.8190/post-207319 @RangerRick said:

possibly grab the hard lines off the ZJ Grand donor axle to re-use on your axle unless you know how to properly cut install & flair brake line fittings safely

However in this post: https://wranglertjforum.com/threads/tj-rear-disc-brake-conversion.8190/page-5#post-734950 @Dan_Goodwin makes no mention of the hard lines.

Does this mean that the soft lines from one of these donor vehicles can't be connected to the hard line on my Dana 35? Is there an off-the-shelf adapter? I have made my own flares for brake lines in the past and I don't really want to do it again.

So far I have a total cost, if the junkyard calipers are ok, of $340+tax.

I can knock $100 off that by using junkyard rotors instead of buying new, but I am not sure how to gauge if a particular rotor is OK to be used. I guess calipers to measure the thickness and check for scratches or gouges, but anything else? I presume warp is not visible to the naked eye.

Thanks! Andy

 

[Rickyd]

Zj Dana 35 and Dana 44 brakets are different. Tj disc brake hard lines can be bought. You'll see whats different when you go.basically nothing interchanges but the brake hose coming from the frame on a drum to disc swap

 

[Rickyd]

I haven't swapped a Dana 35. You might want to grab the Dana 35 specific hardlines?assuming the width and suspension layout make that useful. There are a couple bolts and brackets by the coil buckets and the bolt holding the soft line to the axle you might want to grab?

 

[Rickyd]

For the ebrake cables you can just get 03-06 disc brake versions.they aren't terribly expensive

 

[AndyA]

Thanks! So am I understanding right that if the donor vehicle has a Dana 35 then it is just a straight swap of the soft brake lines?

In that case looks like I need to avoid the Jeep Liberty as that had the Corporate 8.25 axle.

Andy

 

[mrblaine]

Zj Dana 35 and Dana 44 brakets are different. Tj disc brake hard lines can be bought. You'll see whats different when you go.basically nothing interchanges but the brake hose coming from the frame on a drum to disc swap

If you are talking about the backing plates, they are slightly different but nothing that can't be easily overcome. The main difference between the 35 and 44 backing plates is the center hole. The ZJ bolts right up to the 35 with no mods, for the 44 it will have to be enlarged with a drum sander to fit the Dana 44 Set 10 bearing and seal through. The other differences are the hole for the ABS sensor which the ZJ has and the 44 does not. That leaves just the distance between the sliders for the pads which is fixed with abutment clips and some careful grinding or run the ZJ pads.

 

[mrblaine]

Thanks! So am I understanding right that if the donor vehicle has a Dana 35 then it is just a straight swap of the soft brake lines?

In that case looks like I need to avoid the Jeep Liberty as that had the Corporate 8.25 axle.

Andy

Doesn't matter, the hard lines can be easily tweaked to fit. The only ones to avoid are the 03-06 hard lines which have the soft lines crimped onto them. That can be solved with the OEM style flex hoses from Centric which include a tube nut so you can cut and flare if needed.

 

[mrblaine]

For the ebrake cables you can just get 03-06 disc brake versions.they aren't terribly expensive

Yep, and avoid the ones from the ZJ if possible unless you understand to put a spacer on the threaded rod at the adjuster. The ZJ has longer cables relative to the housing than the TJ does so you run out of adjustment for the parking brake.

 

[TJ4Jim]

Yep, and avoid the ones from the ZJ if possible unless you understand to put a spacer on the threaded rod at the adjuster. The ZJ has longer cables relative to the housing than the TJ does so you run out of adjustment for the parking brake.

There is an easy mod to use the ZJ cables that takes about 5 minutes by eliminating 2 pieces to allow for the longer cable. Did mine like this 10 years ago.

 

[Plumber1]

Is this swap worth the trouble, I mean how much better will the jeep stop since a big portion of the stopping is done by the front brakes ?

 

[TJ4Jim]

Is this swap worth the trouble, I mean how much better will the jeep stop since a big portion of the stopping is done by the front brakes ?

Just having an e-brake that I have only adjusted twice in 10 years convinced me. First time when I installed and 6 years later when she was re-framed, thats it

 

[Rickyd]

If you are talking about the backing plates, they are slightly different but nothing that can't be easily overcome. The main difference between the 35 and 44 backing plates is the center hole. The ZJ bolts right up to the 35 with no mods, for the 44 it will have to be enlarged with a drum sander to fit the Dana 44 Set 10 bearing and seal through. The other differences are the hole for the ABS sensor which the ZJ has and the 44 does not. That leaves just the distance between the sliders for the pads which is fixed with abutment clips and some careful grinding or run the ZJ pads.

exactly.

Can you elaborate on the backing plate slider difference from tj to zj?

I used zj backing plates on my rubi axle since they were rotted out. I can hear the rear tj pads shifting in the zj backing plates when braking in reverse.

If i understand you correctly i need to run stainless clips on the pads and clearance the sliders or just put some zj rear pads into the zj backing plates?

 

[mrblaine]

Is this swap worth the trouble, I mean how much better will the jeep stop since a big portion of the stopping is done by the front brakes ?

Zero improvement in stopping ability. Massive improvement for all other aspects. Maintenance, self adjusting, and ease of working on them. I never do the swap except to get rid of drum brakes since I despise working on them.

 

[mrblaine]

exactly.

Can you elaborate on the backing plate slider difference from tj to zj?

The ZJ pads were not set up to use the stainless steel abutment clips that the TJ, Ford Explorer, and Liberty use. If you want to use them, grab a set of 964 pads which should come with the clips or I can send you some, install the clips, fit the pad and remove some material from the reaction bars until the pads fit nicely.

I used zj backing plates on my rubi axle since they were rotted out. I can hear the rear tj pads shifting in the zj backing plates when braking in reverse.

Want some clips to try?

If i understand you correctly i need to run stainless clips on the pads and clearance the sliders or just put some zj rear pads into the zj backing plates?

ZJ pads are longer in the groove spacing end to end IIRC.

 

[mrblaine]

There is an easy mod to use the ZJ cables that takes about 5 minutes by eliminating 2 pieces to allow for the longer cable. Did mine like this 10 years ago.

View attachment 443833

I tend to believe that the factory sets stuff up a certain way so I like to keep it like that. The caution was not so much how to use the ZJ cables but more to avoid clamping a loop in the stock drum brake cables and go get the TJ Rubicon cables. Had I not mentioned the cable to housing length difference, someone else would have.

 

[macleanflood]

So this 1999 Cherokee would have everything I need to convert my 97 Dana 35 to disc brakes?

I'd love to have amore functional emergency brake.

https://eugene.craigslist.org/pts/d/eugene-1999-jeep-grand-cherokee-limited/7638173730.html
-Mac

 

[mrblaine]

So this 1999 Cherokee would have everything I need to convert my 97 Dana 35 to disc brakes?

I'd love to have amore functional emergency brake.

https://eugene.craigslist.org/pts/d/eugene-1999-jeep-grand-cherokee-limited/7638173730.html
-Mac

Isn't the 99 a WJ?

 

[macleanflood]

Isn't the 99 a WJ?

84 to 2001 for XJ. Allegedly has a Dana 44 rear.

Snag the parts for the rear brakes, grab the wiring harness and engine for a maybe 5.2/5.9 conversion. Sell off some other parts and scrap the rest.

-Mac

 

[TJ4Jim]

So this 1999 Cherokee would have everything I need to convert my 97 Dana 35 to disc brakes?

I'd love to have amore functional emergency brake.

[URL]https://eugene.craigslist.org/pts/d/eugene-1999-jeep-grand-cherokee-limited/7638173730.html[/URL]

-Mac

Up to 98 it was a ZJ then became WJ as mentioned so that's a no go on the 99'

 

[TJ4Jim]

The ZJ pads were not set up to use the stainless steel abutment clips that the TJ, Ford Explorer, and Liberty use. If you want to use them, grab a set of 964 pads which should come with the clips or I can send you some, install the clips, fit the pad and remove some material from the reaction bars until the pads fit nicely.

Want some clips to try?

ZJ pads are longer in the groove spacing end to end IIRC.

I get that mindset and its the correct approach. I just remember laying on my back fitting up the ZJ cables trying to understand the purpose of the factory setup and thinking they just wanted to use that main bracket on multiple vehicles so they added pigtail extension.