NEWB Brake & front end question...

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Hey gang,

I have a couple of questions before I go and do my brakes. First of all, I have a 1990 with command trac with 240k that I just got. All the other jeeps that I have owned were with select trac.

Here are my questions:

1. I want to do the brakes, because not sure where they are at from the PO. I usually replace the rotors ( big deal on GC), but is it worth the $22 to buy aftermarket rotors or just turn them?

2. Since the milelage is so high, and I am there, should I just do the bearing/hub assembly or the ujoints? I have some noise there, but not to bad. If I do replace the hub assembly, do I go aftermarket or dealer?

3. OK, here is the big question. When I got the jeep, I had a mechanic change all the fluids in the axles and tc, transmission. But I do get a noise that I have not heard when I put it into 4wd. I know the vaccumm actuvator works, but I see in the factory manual that it uses oil there too. Should I disassemble this and clean it out or not worry about it. Not to familiar with this thing, since I have Jeeps with select trac....

Is there anything else that I should do or look at when I am there?

Thanks in advance,

Bob

is it worth the $22 to buy aftermarket rotors or just turn them?
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I pay almost that much just to get them turned. Buy new and send me a set or two please.
If you tow or are a super go faster I would replace them. Use cheep rotors and just replace them ever time butyou do a brake job. If you get cheep rotor I would not pay big bucks for pads. Go fasters and heavy towers eat the pricey stuff up about a fast as the cheep stuff. (IMO) I tow heavy and the big buck stuff never paid back (IMO)

Yeh,

Our local parts house offers replacement rotors for $22 each and "lifetime" pads for $29. I don't tow with this vechicle any thing heavy, I have GC for that.

They qouted me $112 for the hub/bearing, the dealer wants $250 and other parts stores have said $85. Not sure why the difference?

Thanks,
Bob

Hub/Beraing assemblies or Unit bearings are best found at junkyards. Expect to pay 10 to 15 dollars for one. Serioulsy, you can go get 10 of them for the price of one new. And the time it takes to change one junkyard is well worth it.

i would definitly go for the new rotors vs turned. bout the same price and you have a bit of a better chance with new.

if you do anything with the axle shafts, u joints could be done quite easily and provide with good piece of mind.

Thanks for the input.

How tough is it to do the U-joints? I am going to do the brakes, if I can do the U-joints easily, I like the idea of piece of mind.

Do I need to take off the diff cover to unclip the shafts? What about the goofy motor that engages the front axle?

Thanks,
Bob

the D30 doesn't have c-clips to hold the outer shafts in.
There's one for the disconnect side but you don't need to worry about those.
Undo the unit bearings and then just pull on the shafts, they'll slide right out.
Stuff a rag in the axle tube to keep your gear oil from draining out.

U-joints aren't difficult, but they can be a pain to get the clips off if they've been on there forever.

a BFH is usually needed, a vise works great, I use a balljoint tool to press them out.

Unless they show signs of being bad, or you're pulling the unit bearing anyway I wouldn't bother.
If you do pull the unit bearing make sure you have a torque wrench that can meet the torque requirements. I think it's 180 ft lbs. The other way is to use never seize on the threads and cut the torque requirements in half. The stub shaft nut is critical, it MUST be torqued properly, as it sets the bearing preload in the unit bearing. If the preload is incorrect the bearing will not last long.
Tools you'll need to pull the bearing:
36 MM socket.
A large breaker bar or impact gun.
12 point 13mm socket
a small chisel is usually helpful in seperating the bearing from the knuckle.
Torque wrench to put it all back together.
torque on the 13mm bolts is 75 ft lbs
torque on the stub shaft nut is 180.
Do not take those as gospel, I don't have my FSM in front of me, those are what I think they are.
Edit:
I forgot to mention that the calipers are held on with a 7mm allen head guide bolt. Get yourself a 7mm 3/8 drive socket if you don't already have one, it's a lot easier than an allen wrench.

Cool,
Thanks for the information.

Does one side or the other wheel bearing go bad before the other? Is that true for the U-joints?

So the passenger side does not require me to disassemble the vaccum/axle motor?

Anything else I should do while I am there?

Thanks,

Bob

cherokee4fun said:

Cool,
Thanks for the information.

Does one side or the other wheel bearing go bad before the other? Is that true for the U-joints?

So the passenger side does not require me to disassemble the vaccum/axle motor?

Anything else I should do while I am there?

Thanks,

Bob

Click to expand...

it's quite possible that one side can go bad and the other can be fine.
A seal could tear, water could get in.
Poor alignment could kill the unit bearing, an out of balance wheel even.

Inspect everything, replace what's needed.
I'd highly recommend going through the steering, inspecting all TRE's and boots.
Checking the ball joints
All the rubber LCA, UCA and trackbar bushings.
With that kind of mileage it's likely that a lot of things are worn.

Lot's of these front end parts are cheap, it's just having the time and the tools to do it.
Air tools are a godsend for frontend work, if you can beg some one to let you borrow a compressor and air tools do so.
Better yet, if someone has a well equipped garage ask for a hand. I'm always doing work for friends, the price is usually dinner.