200,000 mile brake system refresh. Thoughts?

[Royal Nonesuch]

I have a 1988 XJ with the stock, vac-disconnect D30 in front and a 29spline 8.25 out of a 2001 XJ in the rear. The 8.25 blew a wheel cylinder running a trail last week, and since I'm at 199,950 miles (~115,000 on the 8.25) I think it's time for a long-neglected brake system refresh. The brakes feel pretty typical/okayish, but I have always had to leave a lot of room in front on the road, because they really don't want to grab. Doubly so if I have a full load of campgear/firewood/whatever - I mostly do overlanding and have to drive a lot of freeways to get there, so that's a bigger deal and it's almost gotten me in trouble before. I've gotten used to it, but it's not ideal or safe really.

After putting some thought into it, I'm going to skip doing a WJ/KJ disc conversion in the rear... reasons being that most reports I read don't really seem to see much of an improvement in braking ability, I don't mind servicing the drums that much, and I'd rather put the money into the front end where the braking forces really count. Also, it's already weird remembering to order axle parts for a 2001 on my 1988 and adding ~1996-1998 WJ or whatever KJ years for brake parts is getting too far into frankenstein territory.

My front wheel hubs are crusty as all hell and I am more than willing to bet they are completely original - I also have recently developed a gravelly bearing noise from the front under coast/decel so bearings/ujoints are probably in order while I've got it torn up. So, that leaves me with the following plan(s):

Rear 2001 8.25, ~115,000miles

• Replace wheel cylinders both sides (Centric Parts 134.62008)
• Replace drum hardware both sides (CARLSON H2309 Pro Kit)
• Re-use the (assuming stock) drums? Should these be replaced?
• Brake shoes were replaced ~4 years ago

Front 1988 D30, 199,950miles

• Replace rotors (CENTRIC 12763003L/R StopTech Sport Drilled/Slotted)
• Replace calipers (RAYBESTOS RC4147/8 Reman)
• Replace pads (included with above calipers)
• Replace outer axle seals: NATIONAL 710202 (front right, disconnect axle) NATIONAL 710068 (font left, disconnect axle)
• Replace outer hub wheel bearings (Timken TMK-SET2)
• Replace upper/lower balljoints (Dana/Spicer 706944X)
• Replace axleshaft Ujoints (Dana/Spicer 5-760X)

Brake Master Cylinder/Booster

• Replace booster check valve (RAYBESTOS CV89000)
• Rebuild master cylinder (RAYBESTOS MK1475 kit)

All of the brake hardlines are good (it's a California Jeep) and I replaced all the softlines with extended new kit when I lifted it four years ago. All of the parts above are split between RockAuto and Summit, biased slightly by price & availability (I have a trip planned end of the month).

Questions:

Calipers: I plan on replacing the ancient original calipers, but it would be cheaper to just order a rebuild kit/O-Ring set and new piston. Is this worth doing to save a few bucks and skip the core return? Are the OEM bendix calipers better or worse in some way?

Brake Pads: I feel like this is probably one of the ways to overspend/overthink an XJ. Also, I can't really find any definitive part #s for things like Hawk or EBC pads. Suggestions?

Brake Master/Booster: I know you can swap this out for a newer XJ booster assembly, but mine works well enough that I figure a minor rebuild should be adequate. I'm open to ideas on this.

While I'm In There: What else am I forgetting? I already have spare diff gaskets.


Notes
This upgrade, as listed, is hovering right about $500 - a bit more than the ~$10 it would cost me to just replace my blown wheel cylinder, but still waaay cheaper than rear-ending a Tesla P85D because my garbage is spongy as hell. I'd like to keep the cost around this amount, and with consideration to keeping things fairly stock.

 

[RCP Phx]

I'd have to dis-agree on the braking ability on a WJ front and rear conversion, but the rear conversion is worth every bit of "non-maintance" and simplicity!

 

[cruiser54]

I'd have to dis-agree on the braking ability on a WJ front and rear conversion, but the rear conversion is worth every bit of "non-maintance" and simplicity!

ABSOLUTELY!!!!!

I've done ZJ rear discs on 2 of my rigs, upgraded boosters etc. Didn't do em all at once either so I got to analyze the effect.

On my Comanche with the Dana 44, I only did the booster.

The discs make a huge difference.

Why not do the ZJ conversion on the rear? Why JK?

 

[cruiser54]

Here's what I would do.

Replace all hoses with braided.

Upgrade the booster master to WJ.

Put 94 to 98 ZJ rear discs on with the proportioning valve upgrade.

Flush the system and bleed it.

 

[lazyxj]

If you are trying to keep the cost down, the Power Stop drum and disc kits, sold by Rock Auto, are hard to beat.
The kits come with everything you need except for a master cylinder and booster.

The ZJ rear discs are a nice upgrade but you get more bang for the buck with upgrading the front discs. The Power Stop premium disc kit works well.
Another suggested front disc upgrade is installing Black Magic pads, they are very impressive and work well hot or cold, when the pads are correctly bed-in.

Your XJ is old, like the rest of ours, replacing the flexible brakes lines with braided lines, as suggested, is good idea.

If your tires are near stock diameter, the Factory brakes can be made to work well.
Once the tire sizes passes 31", IMO, the brakes start needing upgrading.
The ZJ rear discs are simple to do and you can find them in many wrecking yards.
Upsizing the front disc will really yield results, the WJ or Vancos provide the braking power needed for tall tires.

My 2001 XJ has used the 15" Vancos, with the dual 48-mm calipers, for 12 years.
They still work great, especially with the Black Magic pads.
The newer Vancos are available in larger rotor sizes.
If doing it again, I would go with the WJ brakes and upgrade the steering to a OTA setup.

When the Vancos were installed, it had a short, 2" lift and ran on 31' tires, it's stopping power then was excellent.
As the tire diameter and weight increases, braking power will diminish unless upgraded.

 

[Jim Malcolm]

Your brakes not wanting to grab is due to the brake booster. You'd be hard pressed to come up with a <$200 modification that makes a bigger difference in ALL of motorsports. NIGHT and DAY difference.

 

[cruiser54]

Your brakes not wanting to grab is due to the brake booster. You'd be hard pressed to come up with a <$200 modification that makes a bigger difference in ALL of motorsports. NIGHT and DAY difference.

Correct.

 

[smccollamjr]

...Replace all hoses with braided...

This will help more than you think especially if you’re running the stock hoses. Just replacing them with new rubber hoses will help. As the hoses get older the rubber gets weak and kind of balloons out when you fit the brakes.

 

[Anak]

Reading comprehension tells me you have already replaced the stock hoses.

The question regarding reusing the old drums should be answered by the machine shop you take them to for having them turned. They will measure them and tell you if you can keep using them or not. The fact that you blew a wheel cylinder may not bode well for keeping them, but if they can be turned and kept within tolerance I would vote for keeping them. Odds are they are better quality than current manufacture.

I would look into Black Magic pads to try to improve your front braking. I have not run them, but everything I have read says they make a noticeable improvement.

 

[Royal Nonesuch]

Lots of good thoughts and advice! I thought I explained it in the original post, but I really am not looking to do a rear WJ conversion - it seemed, in my (internet) research, that properly adjusted brake drums are basically equal to discs in rear stopping force, unless you're running track with brake fade etc.

I also don't really mind the added hassle of servicing drums because I'm a weirdo. I understand that doing a full front+rear WJ conversion would result in increased braking, but I don't want to get into conversions for reasons already outlined in the original post, namely that I'm sick of trying to keep track of what year I'm ordering parts for. This is a 200,000 mile brake system refresh, not a total modification.

Why not do the ZJ conversion on the rear? Why JK?

If there's anyone I take as gospel, it's you so I'm already behind the curve here. Basically, I'm going for a brake system refresh. I mention JK because they're a direct brake swap on 8.25s from what I've read.

Here's what I would do.

Replace all hoses with braided.

Upgrade the booster master to WJ.

Hoses have already been replaced. Is the WJ master a direct fit, and would it benefit a stock XJ without WJ brake components?

If you are trying to keep the cost down, the Power Stop drum and disc kits, sold by Rock Auto, are hard to beat.
The kits come with everything you need except for a master cylinder and booster.

If your tires are near stock diameter, the Factory brakes can be made to work well.
Once the tire sizes passes 31", IMO, the brakes start needing upgrading.
The ZJ rear discs are simple to do and you can find them in many wrecking yards.

Thanks, I will definitely check out the Power Stop kits. I forgot to mention, but I'm running 31" tires so you're on the mark.

Your brakes not wanting to grab is due to the brake booster. You'd be hard pressed to come up with a <$200 modification that makes a bigger difference in ALL of motorsports. NIGHT and DAY difference.

Correct.

This is reffering to the WJ brake booster mod?

Reading comprehension tells me you have already replaced the stock hoses.

The question regarding reusing the old drums should be answered by the machine shop you take them to for having them turned. They will measure them and tell you if you can keep using them or not. The fact that you blew a wheel cylinder may not bode well for keeping them, but if they can be turned and kept within tolerance I would vote for keeping them. Odds are they are better quality than current manufacture.

Thank you, I thought maybe I was losing it. Good info on the drums; I'll have them checked out.

 

[RCP Phx]

I mention JK because they're a direct brake swap on 8.25s from what I've read.

It's the KJ disc's that are a direct fit.

 

[cruiser54]

It's the KJ disc's that are a direct fit.

Only difference is ZJ caliper mount is needing a little buffing to get it to slide over the axle.

Are KJ Liberty brakes as easy to come by though?

 

[RCP Phx]

They are a dime a dozen at the p-n-p's here, they're mostly 2wd but who cares!

 

[Royal Nonesuch]

It's the KJ disc's that are a direct fit.

Only difference is ZJ caliper mount is needing a little buffing to get it to slide over the axle.

Are KJ Liberty brakes as easy to come by though?

Doh, yeah I meant KJ/Liberty. And it's weird, but I I've started seeing as many if not more KJs than XJs in my local yard inventory. Tons and tons of ZJ/WJs.

 

[cruiser54]

Rarely see them here. Good to know their availability. Boosters????