Cooling and Brake Conversion

I just bought a 88/91 jeep cherokee (91 body, 88 engine). The brakes dont work hardly. I have to use both feet and stand on the pedal just to slowly stop. It has the Bendix abs braking system. Also there is a hole in the radiator and it is the closed system style. Can anyone give me a list of parts I need to convert the cooling system to a 92+ open style? and a parts list for converting to a standard power brake system?

For the brakes you'll need the master/booster from an 87-94 if you want it to bolt up. You can go later model if you want more braking power, but you'll have to make some bushings and such to fit the later booster to your firewall. Some pedal linkage mods are required too IIRC.

For the cooling system, go get the HO style radiator, install it, ditch the heater control valve entirely or hook up the HO style HCV. I just ditched it completely, it's not present on the late models. I just carry a hose splice in case the heater core fails so I can splice the heater hoses togethr.

autozone sells a cheap small coolant recovery tank that fits nicely in the drivers side fender. You'll need to bend the vacuum solenoid for the EGR back about 1/2" if you decide to mount the recovery tank there. I also had to slot my airbox and move it back a touch to clear the filler neck o the radiator so I could open my airbox.

Also, this needs moved to mod tech.

Look into the WJ master cylinder / booster swap. I think there is a "sticky" on it, in the "writeups" section or some such. If I recall correctly, the WJ master / booster combo fits into the early model Jeeps much easier than the later model Cherokee stuff. People report great performance out of this swap.
Note: this is NOT the WJ knuckle / caliper swap. Different projects.

So if I was to have a 96 xj mc laying around it would not bolt right up?

dark92xj said:

So if I was to have a 96 xj mc laying around it would not bolt right up?

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95-96 were odd years. I can't say for certain, Chrysler was changing parts in anticipation of OBD-II and the front clip/firewall redesign.

'95 and '96 brake booster and master assembly will bolt right up to your '91, but since you had the ABS, you will need to either relocate the pin for the booster rod on the brake pedal, or replace the pedal with the one from the donor vehicle. You will have to redo brake lines, etc. but it will bolt up.

I put a '95 booster assy in my '91 with Bendix ABS last year.

Also, is the radiator the stock one from the '91, or is it from the '88? Because '91 is a stock open system.

Begster said:

'95 and '96 brake booster and master assembly will bolt right up to your '91, but since you had the ABS, you will need to either relocate the pin for the booster rod on the brake pedal, or replace the pedal with the one from the donor vehicle. You will have to redo brake lines, etc. but it will bolt up.

I put a '95 booster assy in my '91 with Bendix ABS last year.

Also, is the radiator the stock one from the '91, or is it from the '88? Because '91 is a stock open system.

Click to expand...

good info there.

I stay away from answering questions about 95-96 because I know chrysler was doing some weird things, and I have no personal experience.

Ok so I have the 96 XJ MC to swap in. I also have the small brake lines to the MC. What else is needed for the brake swap? Do you have any info on relocating the pin for the booster rod?

The Radiator im assuming is from an 88 because its a closed system...i cant find a cap anywhere in the engine bay. I got a radiator, upper and lower hoses, the 4 port heater valve, and the heater hoses from the 96 also. I already have a overflow tank and hose. Is there anything else I will need to do the cooling system swap?

Do you have a proportioning valve from the '96, or any newer Jeep? You will have to redo the main hardlines to each wheel, and most likely bench bleed the master.

As for the pin, when I installed the '95 booster, the pin was located too high on the stock '91 pedal. This made it almost impossible (never did get it on) to install the rod onto the pin, and I'm sure if I had it would have led to excessive wear and premature failure. I removed the pedal, and was going to drill a new hole and press the pin out and then back into the new hole, until I realized I had a pedal from a '99 I just parted out sitting around, that happened to have the pin in the perfect place. I did not reuse the large spring that wraps around the mounting tube (you'll know what I'm talking about when you remove the pedal) with the new pedal, it is not necessary for the diaphragm booster as the booster will make the pedal return to the rest position.

'91 pedal on right, showing pin in higher location, '99 pedal on left.


Different view, this time the '91 pedal is on the left, '99 pedal on right.

Spot on with everything said about the 95/96 Master cylinder. Put one in my 91, just bent and reflared the existing lines and used the pedal assembly from the donor.

The only issue I've run into with the cooling system conversion is the temperature sensor. Got lucky on 1 as the new radiator had a port in it that allowed the old sensor and harness to "plug and play." I had to do some makeshift work to get a sensor in another.

I got a power booster and master cylinder from a 96 ZJ at the local JY to install in my 88. Fit right in, no spacer needed on the fire wall. Only thing I had to do was cut and weld the pedal rod and make some new lines going from the MC to the proportional valve. Used my existing prop valve, now the 33's easily lock up when needed. Note I have no ABS. When my radiator takes a crap ill be upgrading to the newer open loop system too.

Well I have the MC/prop valve combo with the booster. The only thing im worried about is making my own brake lines. Isnt there adapters that I can use that will work? I realize this may not be the best way to go but im just trying to fix it to sell.

Also if I do not have the brake pedal can i still reuse my 91 brake pedal?

I couldnt find any adapters around my area. Its just easier to buy the double flared tool at autozone for 20 bucks and do it your self in my opinion. I reused my original brake pedal. The rod from the ZJ had a different eye on the end than mine. I mocked up the new booster with the rod already cut and measured the distance to pedal, then proceeded to cut my old rod from the booster and welded it to the new one. No big deal, whole process took couple hours including going to the auto store and digging around for the right brake lines.