1990 240DL sedan

I've got the left front wheel off; looks like I need a new set of brakes and rotors. Also, while I can freely spin the left front wheel, the right front wheel does not turn freely??? This may be related to my question below.

How do I tell if the calipers are okay? Can this be done visually, or do I need to remove the caliper to inspect it. In either case, what should I be looking for?

thanks

 

Calipers should last the life of the car if the brake fluid is replaced every couple years. Sometimes the pistons get sticky because of moisture in the brake fluid, which leads to corrosion. As long as the pistons move freely it should be OK.

 

you can always get a rebuild kit for the brakes.

 

Don't overlook the brake hoses. If the hoses are cracked and or hard, replace them. As the hoses age they constrict brake fluid.

 

Good comment on the hoses; I'll take a better look at them tomorrow.

I looked further at the wheel related components today to determine what work was needed. Parts that definitely need replacement include: the brakes (and thus rotors), the left lower ball joint, and the left dust cover that sits behind the rotor (eaten away in lots of places by rust).

There was also play in the left wheel bearing, but no noise when I rotated the tire. So I removed the wheel hub to inspect the bearings. Tomorrow I will use a brass drive to remove the bearings and races, clean them, and see if they need to be replaced.

A few questions:

1. The car has 146K miles on it. As far as I know, the wheel bearings have never been replaced or repacked. Is there a certain mileage when they should automatically be replaced, regardless of condition?
2. If the bearings look ok, I was planning to just repack them. Should any of the parts still be replaced, e.g. the races, the sealing washer behind the inner bearing, the sealing ring installed on the spindle before reinstalling the wheel hub?
3. In one of the wheel bearing threads I read “… pull off the dust cap (please don't use channel locks)…” Too late now, but why out of curiosity?
4. Does it make sense to replace the right lower ball joint just because I am doing the left? Currently it looks ok.
5. Same question for the right front dust cover that sits behind the rotor. While rusted, there are no holes in it.

The jury is still out on whether I will replace the calipers. I’ll take a better look at them tomorrow.

Thanks

 

Easy way to tell if a brake hose retaining pressure is to stomp on the brake pedal, let it go, then crack the bleeder on the caliper. Spurt of fluid + restriction somewhere.
Unless a caliper suffers a catastrophic failure, a good rebuild is all they ever need. They only have pistons as moving parts, plus perhaps a slide that needs attention. They are typically comprised of six to ten parts in total and are easy to rebuild as long as no corrosion is present in the piston bores or the piston itself.
I would give the entire system a good bleed, pop the calipers off and thoroughly clean the caliper slides and see how you go.

Regards, Andrew.

 

Any feedback on my 5 questions? I'm especially interested in the wheel bearing questions.

thanks

 

240DL 146K miles

I decided to replace the right dust cover also. I also found the right front caliper was seized, and one of the pistons on the left front caliper looks like it *might* be leaking. I plan to replace both with rebuilt calipers. I had thought about rebuilding them myself, but will skip it this time.

I am still interested in knowing if there is a certain mileage when wheel bearings should automatically be replaced, regardless of condition. Or is it just a case of always repack as long as they are still good.

And should I do the right ball joint as preventative work since everything else is out of the way?

With the wheel bearings, rotors, brakes, calipers, and left ball joint all removed, is there any other preventative work that I should do before reassembly. Or asked another way, are there any other bushings or parts related to the front suspension that typically go, and since it is all open to me now, I might as well do this something else also.

Thanks

First time I ever attempted something like this. I'm learning lots and enjoying it. Luckily, I have warm weather (strange for New England) and time to take my time.

 

Wheel bearings are a replace when required item, easily replaced at a later stage. If yours are good, I'd clean them with kerosene, repack and call it good. They give plenty of warning when they are going out, usually noise.
I would replace the balljoint if it is original at those kms, they are cheap and the work required to get to them again is large. If it is O.K now, it will not be at 200k miles.
You should also look at tie rod ends, again cheap and easy to replace. Any significant play up and down in any balljoint is a fail.
Inspect your struts for any signs of fluid weeping, also check the condition of the bump rubbers on the struts.
Lower control arm bushes should also be looked at, some light surface cracking of rubber is O.K, large cracks, rubber extruding out of the bushes or the bush centre sleeve sitting significantly offset in the rubber bush means replacement.
Spending money on front suspension parts is really cheap, and the gains in road holding and improving the ride quality of a car far outweigh the money spent.

Regards, Andrew.