skinnyg

Hi, I have been working on installing Liberty rear discs on a 29 spline 8.25 Cherokee axle. This is in my Mj Comanche. Is there any reason I couldn't install the right backing plate on the left side, and left on right. This would put the calipers in front of the axle. This would help with the parking cable and brake hose/line routing. I know about the bleeder position on the calipers, just not sure about the leading/trailing edge issues with the pads and shoes. thanks

Photojared

I'm not sure how the liberty parking brake is set up, but the ZJ parking brake is activated by a tab that gets pulled towards the front of the vehicle. If I were to switch them sides, the pull tab would get pulled towards the rear of the vehicle as would not be easier.

They are designed/engineered to go on one way, I'd probably just leave it.

Firehawk068

Both the (KJ) Liberty, and the (ZJ) Grand Cherokee use parking brake shoes that are mounted inside of the brake rotor...........
The parking brake has nothing to do with the calipers themselves.....


The liberty calipers are also shared by Ford Explorer/Mercury Mountaineer from 2001-2009....................


The backing plates are most likely oriented so that the emergency brake cable attaches facing forward, however I am not certain on this............
You might be able to swap backing plates left/right, and install the parking brake shoe hardware on the correct side, so that the cables actuate them correctly....
I am not sure how it would matter for brake line/hose routing if you mounted them in front of the axle vs. the rear of the axle.........
The hoses are just going from the caliper to the top of the axle tube regardless of where they are mounted.........
The hard lines still go from the "T" along the tops of the axle tubes.

salad

Left needs to stay left and right needs to stay right. Two reasons:

Caliper location is chosen that way so the brakes actually work well. You'll notice all disc brakes have calipers on the rear. This is how pads are set up for leading/trailing edges.

The parking brake is actuated with a lever that, if flipped, would have to be pulled towards the rear. Caliper orientation has nothing to do with this, the levers are in the middle.

skinnyg

I do want the cables coming out the back. Stock, they point slightly down and to the front, then have to double back towards the rear and then back again 180 degrees and up to center of the bed just forward of the pumpkin(Comanche).
If turned around the cables would point slightly up and towards the rear. Routed through the leaf spring (SOA plenty of room), around the shocks and in a large 180 loop back to the front. Lots of slack for suspension travel. I am working with cables from the liberty which are too long either way but the routing looks good this way, just need the right length cables.
Also the short rubber hose for the caliper, stock it loops tightly 180 degrees from front to back. If turned around it would point to the rear with a small curve. I will be making the hard lines and want to keep them on the rear and top of the axle(like originals).


My concerns for starting this post are for how the brakes will react to the different mounting. Mainly that the calipers will still work and the brakes will function properly, I cant see how they wouldn't, but that's the question. Also I want to keep the parking brake working properly.

skinnyg

Also with the cables coming out the front, any small trees/saplings that I might be driving over/through could get wedged between the wheel and leaf spring, which is right were the cable is. If the cable is positioned to the rear, then not a big deal (unless backing over this stuff). I already installed the backing plates(months ago) in the normal position, but have not put the gear oil in yet. I have been working on this MJ for over 3 years and not driven it yet. I am trying to get it on the road for this winter.

CobraMarty

I mounted my Big David sourced rear discs and put the calipers in front, swapped left for right, like the OP asked. No problems with braking or wear. Yes the levers pull to the rear and with longer cables they will loop around 180* and have better slack/droop/protection. New hard lines all tucked up and on top of the axle. No pics, but I will look later, it is cold outside.

This is on a MJ D44 in my XJ. I don't think that it would matter, D44 or 8.25.

I don't know if mounting the rear calipers in front of the disc will help rear end squat during braking vs. lifting while braking. BMW, Porsche, etc all put the rear calipers in front of the discs.

Firehawk068

Certainly, the parking brake shoes aren't going to care which side they are mounted on, as they are only used to hold the vehicle when parked.........

The pads themselves aren't going to care which way the rotor is turning.........They just grab the rotor and try to slow it down.....
Sometimes they are chamfered a certain way, but looking at the rear pads for the Liberty, it looks like they are chamfered on both ends.......

Caliper brackets sometimes are reenforced on a certain side depending on which way the majority of braking force will be applied, or the caliper hardware sometimes is different for one end of the caliper vs the other.
Looking at the calipers and brackets for the Liberty, they look pretty symetrical, so it probably wouldn't matter what side you mounted them on.
Just make sure you mount the calipers with the bleeder screws at the top...

CobraMarty

That's why you have to swap left to right and right to left.

Firehawk068

Whether they are mounted in front or rear of the axle, the braking force will be the same................It will try to rotate the pinion downwards during braking.................(at least when you are driving forward)

CobraMarty

Pinion down with either on braking, use traction/anti wrap bar to control. It probably helps some on rear squat vs. Lift just like on front where front calipers mounted on the rear of the disc helps prevent nose dive on braking. How much on XJs ? Fun to be different. The cables do work out better routing.

ZJMAX

This is not true of all disc brakes. GM 1/2 ton trucks and suv rear disc brakes have the calipers to the front side of the axles, as well as some camaros and firebirds to name a few. Just throwing that out there.

Max

cdn_xj

x2

caged

even the grand cherokee srt8 and i think the regular grands now have the calipers to the front also.