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-   -   Rear disc brake conversion (http://www.wranglerforum.com/f210/rear-disc-brake-conversion-49806.html)

adkjoe 04-28-2010 12:58 PM

Rear disc brake conversion
 
So while my funds are building back up I need a cheap Jeep project. I'm thinking of doing this
D35 Disc Brake Conversion - 1

Seems pretty straight forward, theirs plenty of grand Cherokees in the yards around. Besides a 1996 does anyone know any other years I can use? I would imagine I could use any grand Cherokee with a D35c right? Has anyone done or attempted this mod? any advice?

Also, when taking the backing plate off of the donor Cherokee I need to remove the c- clips and pop out the axles to get it off correct?

Jerry Bransford 04-28-2010 01:27 PM

Yep the axle shafts have to come out to get the backing plate off.

If you're wanting to do a rear disk brake conversion to make brake maintenance easier, go for it. If you're wanting to do it for better braking, save your $$$.

Converting rear drum brakes that are working properly to disk brakes won't improve your braking performance or make you stop any faster. I did the rear drum to disk conversion on my TJ years ago when I had more $$$ than experience with rear brakes and was bummed that there was absolutely no discernable improvement in braking afterwards. I knew there wouldn't be much, if any at all since the rear brakes only provide 20% max of the total braking, but I was hoping there might have been... nope. :)

adkjoe 04-28-2010 01:34 PM

Yea I'm mainly doing it for easier maintenance, Drum brakes piss me off :)

Shouldn't cost me much as long as I can find caliper in good shape. I will put a fresh pair of rotors and pads on but use the junkyard calipers and backing plate. I know the axles have to come out to get the drum plate off but they also has to come out to get the plate off of the disc brakes on the Cherokee?

Is this something you would do again Jerry even knowing it didn't improve braking?

Jerry Bransford 04-28-2010 01:44 PM

I wouldn't do it again. Rear brakes do so little work that they don't wear out quickly enough for me to worry about the slight extra work to replace drum brake shoes & adjust them. :)

daanbc 04-28-2010 03:19 PM

Quote:

Originally Posted by Jerry Bransford (Post 611035)
I wouldn't do it again. Rear brakes do so little work that they don't wear out quickly enough for me to worry about the slight extra work to replace drum brake shoes & adjust them. :)

Jerry, would you reccomend someone to convert to rear disk's if they tow every now and then? Would it make a difference at all? I will be switching out the tranny fluid with synthetic next week. I hear the synthetic has a higher burn rate then reg. tranny fluid. For that bit of $$ I'd like to play it safe then sorry later. Even though I don't tow alot, when I do I want to make sure I do it the best way possible. (with a jeep) that is. LOL.

chop110 04-28-2010 03:43 PM

Just to chime in, Jerry is right. I converted my rear from drum to disc three years ago and have not really noticed any difference in braking power (I felt like a sucker). I have recently looked at my rear pads and they still have a ways to go before replacing.

If anyone else is interested in more braking power, I've heard good things from double piston kit from VANCO. Although at $750 a pop, it is really pricey.

VANCO Power Brake Systems Wrangler/Commanche/Grand Cherokee/Cherokee front brake upgrade kit Reviews, Ratings, Specs & Prices

adkjoe 04-28-2010 03:50 PM

Well it seems like a pretty easy project and I can get the parts cheap from the junkyard and I need something to do. I've been procrastinating taking off my fenders and painting so this will keep me busy while I procrastinate some more...I just hate drum brakes and want them gone, I don't really care about weather it will brake better or not but I thought for sure it would so thanks for the heads up guys i'm surprised.

Jerry Bransford 04-28-2010 03:58 PM

Quote:

Originally Posted by daanbc (Post 611125)
Jerry, would you reccomend someone to convert to rear disk's if they tow every now and then? Would it make a difference at all? I will be switching out the tranny fluid with synthetic next week. I hear the synthetic has a higher burn rate then reg. tranny fluid. For that bit of $$ I'd like to play it safe then sorry later. Even though I don't tow alot, when I do I want to make sure I do it the best way possible. (with a jeep) that is. LOL.

If your trailer is heavy enough to where you're worried about that, then the trailer should already have brakes on it. But even so, the rear brakes provide such a low percentage of the overall braking, 20% of so from the rear and 80% from the front, that rear drums are still fine even for towing.

And yes, synthetic ATF can withstand higher transmission temps than conventional ATF can before it is damaged. :)

EdJonesJeeper 06-10-2010 08:24 PM

I'm sitting on a tj d44 in my garage for 4 more weeks and was thinking about it.
I've done drum brakes and they were difficult but not impossible to do in your driveway. And I'm no mechanic.

You might have convinced me to save my $$$. Although I could tell the differance when I had my 318 ZJ on 31's with 2"BB.

How thought how could you FORCE the rears to pull more than 20% of the weight?
Seems like you could set up some sort of valve/ballast.

I've always wanted an emergency break that pulled the disk instead of the drum inside the disk. Drifters have something similar. I think that would be sick in the Jeep!!!!... uhmm How could I do that on a budget?

Rmga420 10-12-2015 09:59 PM

I tried this on my 88 yj. I got a donor axle off a 96 zj thinking it was all I was gonna need. Wrong. My lack of experience reared its ugly head again lol. Lesson learned. I'm still in the process of working out all the bugs. Just thought I'd post this for anyone thinking about doing this to their Dana35 with BOLT ON axles.

TJ4Jim 10-13-2015 05:58 AM

I would do it again just to have an E-brake that works the same every time I use it.

Digger84 10-13-2015 06:21 AM

Most TJ rear disc setups use a mini rear drum for ebrake/park brake only

The original owner of mine set it up as a to be towed vehicle with full size warn manual hubs on all four wheels and a warn full floater kit on rear D44

That kit used a Cadillac Eldorado rear brake caliper and a CJ rotor. That caliper has a built in park brake no drum involved

After a little change in length of lever below hand brake cable (bolted on about one inch extension$ to increase cable travel) I now have excellent parking brake on my 98 sport that is not directional biased like the stock mini drum on my wife's 04 rubi

Plus Rivera's and Toranado's and Eldorado's are plentiful at up pull it yard

Cole Man 02-17-2016 07:29 AM

Im reviving this thread because I plan or replacing my malfunctioning drums very soon. Is the parts in Stus write everything that is needed? Ive read other threads and it seems more in depth than that.

TJ4Jim 02-17-2016 09:17 AM

Quote:

Originally Posted by Cole Man (Post 24132545)
Im reviving this thread because I plan or replacing my malfunctioning drums very soon. Is the parts in Stus write everything that is needed? Ive read other threads and it seems more in depth than that.

I ordered new E-brake cables and rear brake hoses for a 98' GC (donor vehicle) as if I recall Stu's site does not get into that clearly. I also welded tabs on the rear to mount the brake hoses and I modified the e-brake splitter assembly by removing one link to allow for the longer GC cables.

I would probably figure on replacing the axle seals while the axle's are out.

It works great and I have not touched the setup in almost a year, including not having to re-adjust the e-brakes.

Mattel 02-17-2016 09:21 AM

IM in the middle of a 8.8 swap.

I think you guys may be missing something.

Drum brakes require less fluid pressure to activate than Disk brakes.

The master cylinder has a proportioning valve that adjusts the pressure for the rear and the front.

in any hydraulic system, if you have the wrong pressure you will not take full advantage of the additional stopping power.

Im at the point of trying to figure this out, can we put our heads together and look at this issue for a bit?

Cole Man 02-17-2016 09:24 AM

Ive read the proportioning valve is the same for TJs drums or discs.

Jerry Bransford 02-17-2016 10:41 AM

Quote:

Originally Posted by Cole Man (Post 24134329)
Ive read the proportioning valve is the same for TJs drums or discs.

What you read is correct.

Cole Man 02-17-2016 11:34 AM

So it really is bolt on? I just have to see how the rubber lines connect to the tj hard lines and figure out the e brake cabel

Big Bad John 02-17-2016 12:32 PM

Wow I'm really surprised that there would be no difference in stopping power noticeable. My old Cherokee had drums in the rear just like my TJ does, and every time those brakes got wet they pretty much ceased to work, although they never worked that well to begin with. I also constantly had to tighten the emergency brake cables. I'm having the same problem with my e-brake now, but the TJ's a 5 speed so I have no "park" gear to leave it in. The only way I can stop from rolling is leave it in reverse.... Maybe I'll just rebuild the drums and save the cash for something else.

freeskier 02-17-2016 12:41 PM

Quote:

Originally Posted by Cole Man (Post 24137009)
So it really is bolt on? I just have to see how the rubber lines connect to the tj hard lines and figure out the e brake cabel

There's nothing special about the brake lines, it's all just standard stuff for 3/16" hard lines.

For e-brake just buy cables for a Rubicon.

Cole Man 02-17-2016 12:58 PM

Ok Im just pretty unfamiliar with brakes and brake lines in general. I wasnt sure if Id have to "flare" a line or anything or if it would just screw together or what honestly.

YJeff 02-17-2016 02:16 PM

I just finished the d-35 with drums to a D-44 with discs.
Unfortunately there was no improvement in braking at all

Cole Man 02-17-2016 02:40 PM

Im not expecting gains in stoppimg power rather just looking for easy maintenance and reliability.

TJ4Jim 02-17-2016 02:46 PM

Quote:

Originally Posted by Cole Man (Post 24138785)
Ok Im just pretty unfamiliar with brakes and brake lines in general. I wasnt sure if Id have to "flare" a line or anything or if it would just screw together or what honestly.

I did not see how it could be accomplished without performing new flairs into each of the brake hoses. Each of the brake lines terminate at where the wheel cylinders used to be so I cut several inches off each hard line and re-flared to adapt to the hoses.

Cole Man 02-17-2016 03:08 PM

Well I guess Ill just have to learn then and rent the tools

freeskier 02-17-2016 05:08 PM

Quote:

Originally Posted by Cole Man (Post 24141289)
Well I guess Ill just have to learn then and rent the tools

You can also buy pre made lengths of brake line that are already flared with fittings.

Jerry Bransford 02-17-2016 06:07 PM

Quote:

Originally Posted by Cole Man (Post 24141289)
Well I guess Ill just have to learn then and rent the tools

It's not hard to learn how to perform the double-flare that is required. Rent/borrow a double-flare tool and do a couple practice flares on the part of the hard line you cut off and you'll be good to go.

Mattel 02-18-2016 06:48 AM

a flair tool is cheap! Just pick one up for $10 at hardware store. Great idea to cut and practice on old hard line.

I found instead of steel line I found harder stainless steel lines for $10 for short one and $17 for long one.

Im re-using the main line and cube splitter and just bending the new lines, if you bend your own lines you can locate them in a place that cannot be smashed or damaged during your wheeling.

Great news on the proportion valve! You just saved me research time! u guys rock!

Well, its back to the garage tonight to paint my new trusses and more research!

TJ4Jim 02-18-2016 05:49 PM

Quote:

Originally Posted by Mattel (Post 24153689)
a flair tool is cheap! Just pick one up for $10 at hardware store. Great idea to cut and practice on old hard line.

I found instead of steel line I found harder stainless steel lines for $10 for short one and $17 for long one.

Im re-using the main line and cube splitter and just bending the new lines, if you bend your own lines you can locate them in a place that cannot be smashed or damaged during your wheeling.

Great news on the proportion valve! You just saved me research time! u guys rock!

Well, its back to the garage tonight to paint my new trusses and more research!

Have you tried the double flare on the SS tube yet, I had a bitch of a time due to the hardness.

Caselogik 06-05-2016 02:09 PM

Just to chime in with a different perspective; depending on your taste, this will either look cool and be neat or like ka-ka but I have a two master cylinder/lever set-up similar to tractor brakes on a Volkswagen. Drum brakes will work. Lots of surface area contact. The reason they brake less than the front is because there isn't as much weight back there to keep then turning during usage and you can imagine how dangerous a short jeep with locked up rear wheels could be. I bought an aftermarket lock box console at the junk yard for $20 so Imma cut it up and see if I can mount the levers and master cylinders in it and make them look decent......lower the top and just have slits for the levers so I can use boots and the whole mess won't be seen. If it looks good I'll plum it in. If not....well I've learned a little. Point is that with a separate master cylinder for each brake the WILL help you stop right up to the point you lock them down and start sliding! I also drilled my drums and while it's not like running racing calipers, it does noticeably help some.


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