Oddball Dragging Caliper Issue - Page 2 - PeachParts Mercedes-Benz Forum

Skippy · #16 03-16-2013, 12:51 AM

The crush washer is in there. What happens if you tighten it past the tolerance and then loosen it again?

I did not know it was available separately for a low price.

whunter · #17 03-16-2013, 01:19 AM

Quote:

Originally Posted by Skippy

The crush washer is in there. What happens if you tighten it past the tolerance and then loosen it again?

I did not know it was available separately for a low price.

Replace the crush sleeve and start again.

.

Skippy · #18 03-16-2013, 09:00 PM

Quote:

Originally Posted by Stretch

Remove brake disc (caliper etc).

Clamp a magnetic base to the side of the trailing arm (I assume you don't have aluminium ones fitted!). If this doesn't work then get something big and heavy that won't move {tool kit?} and position it at a suitable distance from the hub so that you can...

...Position your clock gauge / DTI so that the probe will run on the surface of the hub. Turn hub by hand and watch how far that little needle spins. As it isn't a really smooth machined surface you will get some variation in needle output (?!).

Done. Maximum variation .006 inch. What measurement constitutes "ok"?

Quote:

If the hub is OK then check to make sure that the bearing clearance is still good => pull hub towards you and away from you - in and out towards and away from the differential.

Less than .001 inch. Too tight. It wasn't before

Quote:

If that is OK put the disk brake back on and repeat the test above.

Alternatively you might find it easier to check run out on the end of the hub - that would be checking for out of roundness in a vertical direction instead of lateral direction.

Runout check - YouTube

Maximum variation .010, but almost all of that appears to be from some small nicks in the surface where the dial indicator was making contact. On the smooth parts is was more like .001 inch variation.

Skippy · #19 03-16-2013, 09:19 PM

I also tried putting some lug bolts in without the wheel in place. I found you can put them in near the top without interfering with any parking brake components. Same as with the wheel-easy to turn when just snug, much harder once tightened. I noticed when I released the torque on the bolts that the lower part of the rotor moved slightly away from the hub, while the top part didn't. This led me to believe that I do have the hub in crooked, which probably also means bearing races still not fully seated. I got out the BFH and gave the hub a few good whacks in the right direction. I found the bearing end play was suddenly nearly within spec, and when I installed the wheel, I found it still harder to turn than it should be, but much less bad than before. I will be taking it for a test ride shortly to see how hot that rotor gets. I think it may be good enough now to get me to work and back when it rains next week. I know I should pull the thing apart, change crush washers, and put it back together, but that will have to wait until next weekend at the earliest.

whunter · #20 03-16-2013, 11:32 PM

Quote:

Originally Posted by Skippy

I also tried putting some lug bolts in without the wheel in place. I found you can put them in near the top without interfering with any parking brake components. Same as with the wheel-easy to turn when just snug, much harder once tightened. I noticed when I released the torque on the bolts that the lower part of the rotor moved slightly away from the hub, while the top part didn't. This led me to believe that I do have the hub in crooked, which probably also means bearing races still not fully seated. I got out the BFH and gave the hub a few good whacks in the right direction. I found the bearing end play was suddenly nearly within spec, and when I installed the wheel, I found it still harder to turn than it should be, but much less bad than before. I will be taking it for a test ride shortly to see how hot that rotor gets. I think it may be good enough now to get me to work and back when it rains next week. I know I should pull the thing apart, change crush washers, and put it back together, but that will have to wait until next weekend at the earliest.

You have:
#1. The rotor is not on the mount - alignment PIN = cocked on the hub.
#2. Received - installed the wrong brake pads = too thick.
#3. Received - installed the wrong rotors
#4. Seized piston failing to fully seat = rebuild or replace caliper.

.

Skippy · #21 03-17-2013, 12:28 AM

Quote:

Originally Posted by whunter

You have:
#1. The rotor is not on the mount - alignment PIN = cocked on the hub.
#2. Received - installed the wrong brake pads = too thick.
#3. Received - installed the wrong rotors
#4. Seized piston failing to fully seat = rebuild or replace caliper.

.

Not #1 as I am aware of that pin and the hole in the rotor that it goes in.
If #2 how come I didn't have any problems from the time of their installation in 2005 until now?
With #3 I've had an identical issue while using the old rotor from 2005 as well as a new one. The old one worked fine for 7+ years.

That leaves #4 as appearing fairly likely, but it seems suspicious to me that the issue pops up simultaneously with a bearing change.

I'm thinking about swapping calipers side to side to see if the issue follows the caliper. That would put the bleed screws in the wrong place, so I don't know if I'd be able to bleed them satisfactorily.

whunter · #22 03-17-2013, 01:38 AM

Quote:

Originally Posted by Skippy

Not #1 as I am aware of that pin and the hole in the rotor that it goes in.
If #2 how come I didn't have any problems from the time of their installation in 2005 until now?
With #3 I've had an identical issue while using the old rotor from 2005 as well as a new one. The old one worked fine for 7+ years.

That leaves #4 as appearing fairly likely, but it seems suspicious to me that the issue pops up simultaneously with a bearing change.

I'm thinking about swapping calipers side to side to see if the issue follows the caliper. That would put the bleed screws in the wrong place, so I don't know if I'd be able to bleed them satisfactorily.

You can't swap the rear calipers from side to side.

It puts the air bleed screw on the bottom.

I rebuild all of my calipers every 4 - 6 years.

.

Stretch · #23 03-17-2013, 02:44 AM

Quote:

Originally Posted by Skippy

I also tried putting some lug bolts in without the wheel in place. I found you can put them in near the top without interfering with any parking brake components. Same as with the wheel-easy to turn when just snug, much harder once tightened. I noticed when I released the torque on the bolts that the lower part of the rotor moved slightly away from the hub, while the top part didn't. This led me to believe that I do have the hub in crooked, which probably also means bearing races still not fully seated. I got out the BFH and gave the hub a few good whacks in the right direction. I found the bearing end play was suddenly nearly within spec, and when I installed the wheel, I found it still harder to turn than it should be, but much less bad than before. I will be taking it for a test ride shortly to see how hot that rotor gets. I think it may be good enough now to get me to work and back when it rains next week. I know I should pull the thing apart, change crush washers, and put it back together, but that will have to wait until next weekend at the earliest.

The "run out" measurements that you made indicated that the hub was running true - well as true as you could expect when making measurements on rough surfaces. That was good.

However, now you've been having a bit of hammer time I think the last bit I've highlighted seems to be the best idea. Rewind and start again.

Do you think that there's a possibility that some how the hub was positioned too far into the trailing arm and so the position of the brake disc is wrong for the position of the caliper? If so this would mean the bearings are shot / wrong...

...in your first post you talk about the bearing seats / bearing cups not being seated properly - could this have been the problem all along?

whunter · #24 03-17-2013, 02:58 AM

Quote:

Originally Posted by Stretch

The "run out" measurements that you made indicated that the hub was running true - well as true as you could expect when making measurements on rough surfaces. That was good.

However, now you've been having a bit of hammer time I think the last bit I've highlighted seems to be the best idea. Rewind and start again.

Do you think that there's a possibility that some how the hub was positioned too far into the trailing arm and so the position of the brake disc is wrong for the position of the caliper? If so this would mean the bearings are shot / wrong...

...in your first post you talk about the bearing seats / bearing cups not being seated properly - could this have been the problem all along?

Yes, it is possible.
The Hub would be out of alignment with the caliper center point.

.

Skippy · #25 03-26-2013, 05:00 PM

Last week I realized I had to fly out on orders for a long weekend of playing Navy. I messed around with that wheel assembly for a bit. The crush spacer is definitely done. It managed to make it the 29 miles to the airport and then back without getting too hot or setting itself on fire. New crush spacers (3 of them just in case) ordered just now. Unfortunately the expected ship date is 5 Apr.

whunter · #26 03-27-2013, 12:17 AM

Quote:

Originally Posted by Skippy

Last week I realized I had to fly out on orders for a long weekend of playing Navy. I messed around with that wheel assembly for a bit. The crush spacer is definitely done. It managed to make it the 29 miles to the airport and then back without getting too hot or setting itself on fire. New crush spacers (3 of them just in case) ordered just now. Unfortunately the expected ship date is 5 Apr.

The bearings will be toast.

.

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