John (Avanteone) and I just completed this and it will give you an idea how tenacious he can be when solving problems on the world's worst Jeep, the Big Woody....here is the short tech article. Longer version follows.
Step 1. Buy an 8.8 w/discs
Step 2. Be done with it
Now for the longer "polishing a steaming turd" version:
I came across a set of rear discs from a '94 Lincoln Towncar in a PAP wrecking yard. Cherokeekid convinced me that the parts were all there and that with some work it would be OK on my D35. It would actually be easier on a D44 but I don't have one yet and that was, to some degree, the reason for doing this...to have a setup that could be retrofitted easily to a new axle down the road. So I plunk down my $36 (begrudgingly for those that know me) and drag home all this stuff...rotors, calipers, brackets, etc.
John and I tore into it last weekend. Here's a recap of what we did to make this work. It assumes that you know how to remove drum brakes and hardware and are familiar with non c-clip axles.
First issue, we needed a spacer to move the caliper bracket out a slight amount to allow room for the pads and rotor to meet in the same place. Mike had suggested modifying a pair of TJ axle retainers. We got those and then added the holes to match our axle retainer pattern.
Next we cut slots in them to allow them onto the axle shaft without pressing on and off the bearings. Here is where we learn that the tone rings on an ABS shaft screw everything up. Thankfully I had my spare shafts which are now my primary shafts...non-ABS. We put the spacers onto those shafts and proceeded to mount the caliper brackets.
The brackets can be used caliper forward or backward as they are the same right or left. The DS is normally a rear caliper, the PS is a front mounted caliper. We needed to grind the PS caliper mount to work as there was some material to get out of the way. We wanted to mount both in the rear to have the brakelines behind the axle to avoid snagging on limbs, rocks, etc. If the PS had been mounted the other direction they would have been OK but possibly more of a risk to the brakeline. Keep in mind that if you mount in this fashion the bleeder is on the bottom on the PS and the caliper needs to be removed and then flipped over to properly bleed it. Not doing this makes it a PITA and, uh, the brakes don't work so hot.
We now realize that the rotors don't fit over the axleshaft flange and do not fit over the shoulders of the lug studs. We spend some quality time with a variety of interesting tools...grinders, Uni-Bits, carbide die grinders, 2 different drill motors....yada yada yada. The rotors now fit.
We then put everything together to realize the drum-in-hat parking brake components don't fit without some more room. Room we don't have. So out came the parking brake components.
We bolt things up again and everything fit...until we tried to turn the wheels which were locked solid. We realized the inner brake pad was not quite centered because we could have used a tiny bit more spacer and the caliper is biased toward the inside. This caused it to bind and freeze the rotor. We go next door to the machine shop and run the inner pads on the belt sander, running off a few thousandths of material allowing them to fit.
So now that everything should fit we put it all back together...good thing we're getting good at this. We immediately took the rotors off as we had discovered the lip on the rear of the drum-in-hat was sticking out and causing some interference. To the brake lathe we went to cut off the lip.
Now that everything fits (not really) we realized that the 15" diameter 4.50" backspaced wheels were making contact with the calipers. Off come the wheels and out comes the grinder where about 1/8" of material came off the caliper bodies on the outer side. Really fancy one-off black spray painted calipers are the result.
Now that everything fits (it really does this time) it's time to bleed a Bendix 9 integrated ABS system. We didn't quite get it right the first time and came back later, after some sleep and some cocktails and tried again.
First you press the brake pedal, engine off, 50 times to reduce the pressure from the accumulators, starting in the right rear, you really don't care about this part...let's be honest...it's just kinda messy and boring.
Final analysis, the brakes work really well. The front/rear bias feels very good. The actuator (ABS master cylinder) seems to provide plenty of fluid and the pedal feel is better than with the drums.
So here's the Mastercard moment:
Brake parts from the PAP: $36
New brake pads and hoses: $65
Breakfast at McDonald's that should have been the only meal purchased that day, but wasn't: $12
Spending a total of 15 hours with my best buddy John in the shop during a 25* cold snap working on arguably the most difficult Jeep ever built:
Priceless
Step 1. Buy an 8.8 w/discs
Step 2. Be done with it
Now for the longer "polishing a steaming turd" version:
I came across a set of rear discs from a '94 Lincoln Towncar in a PAP wrecking yard. Cherokeekid convinced me that the parts were all there and that with some work it would be OK on my D35. It would actually be easier on a D44 but I don't have one yet and that was, to some degree, the reason for doing this...to have a setup that could be retrofitted easily to a new axle down the road. So I plunk down my $36 (begrudgingly for those that know me) and drag home all this stuff...rotors, calipers, brackets, etc.
John and I tore into it last weekend. Here's a recap of what we did to make this work. It assumes that you know how to remove drum brakes and hardware and are familiar with non c-clip axles.
First issue, we needed a spacer to move the caliper bracket out a slight amount to allow room for the pads and rotor to meet in the same place. Mike had suggested modifying a pair of TJ axle retainers. We got those and then added the holes to match our axle retainer pattern.
Next we cut slots in them to allow them onto the axle shaft without pressing on and off the bearings. Here is where we learn that the tone rings on an ABS shaft screw everything up. Thankfully I had my spare shafts which are now my primary shafts...non-ABS. We put the spacers onto those shafts and proceeded to mount the caliper brackets.
The brackets can be used caliper forward or backward as they are the same right or left. The DS is normally a rear caliper, the PS is a front mounted caliper. We needed to grind the PS caliper mount to work as there was some material to get out of the way. We wanted to mount both in the rear to have the brakelines behind the axle to avoid snagging on limbs, rocks, etc. If the PS had been mounted the other direction they would have been OK but possibly more of a risk to the brakeline. Keep in mind that if you mount in this fashion the bleeder is on the bottom on the PS and the caliper needs to be removed and then flipped over to properly bleed it. Not doing this makes it a PITA and, uh, the brakes don't work so hot.
We now realize that the rotors don't fit over the axleshaft flange and do not fit over the shoulders of the lug studs. We spend some quality time with a variety of interesting tools...grinders, Uni-Bits, carbide die grinders, 2 different drill motors....yada yada yada. The rotors now fit.
We then put everything together to realize the drum-in-hat parking brake components don't fit without some more room. Room we don't have. So out came the parking brake components.
We bolt things up again and everything fit...until we tried to turn the wheels which were locked solid. We realized the inner brake pad was not quite centered because we could have used a tiny bit more spacer and the caliper is biased toward the inside. This caused it to bind and freeze the rotor. We go next door to the machine shop and run the inner pads on the belt sander, running off a few thousandths of material allowing them to fit.
So now that everything should fit we put it all back together...good thing we're getting good at this. We immediately took the rotors off as we had discovered the lip on the rear of the drum-in-hat was sticking out and causing some interference. To the brake lathe we went to cut off the lip.
Now that everything fits (not really) we realized that the 15" diameter 4.50" backspaced wheels were making contact with the calipers. Off come the wheels and out comes the grinder where about 1/8" of material came off the caliper bodies on the outer side. Really fancy one-off black spray painted calipers are the result.
Now that everything fits (it really does this time) it's time to bleed a Bendix 9 integrated ABS system. We didn't quite get it right the first time and came back later, after some sleep and some cocktails and tried again.
First you press the brake pedal, engine off, 50 times to reduce the pressure from the accumulators, starting in the right rear, you really don't care about this part...let's be honest...it's just kinda messy and boring.
Final analysis, the brakes work really well. The front/rear bias feels very good. The actuator (ABS master cylinder) seems to provide plenty of fluid and the pedal feel is better than with the drums.
So here's the Mastercard moment:
Brake parts from the PAP: $36
New brake pads and hoses: $65
Breakfast at McDonald's that should have been the only meal purchased that day, but wasn't: $12
Spending a total of 15 hours with my best buddy John in the shop during a 25* cold snap working on arguably the most difficult Jeep ever built:
Priceless
By the way how did your other project go? go/no-go?
weekend.
