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View Full Version : Sticking caliper (again) on pass rear (2004, 2500 series)


rob99rt
02-09-2014, 11:46 PM
This is the second time in about a year this same wheel has had issues. I replaced the caliper assembly last year around the same time last year and after everything was buttoned back up it worked just fine... both rear brakes seemed to brake equally and temps were within 10-15 degrees of each other as checked with a hand-held laser thermometer thing...

Well, when we got to church this morning I could smell something pretty hot on the right rear and I could feel the heat coming off of it. FWIW, it's only a 13 or so mile trip and it's mostly freeway. So, clearly there's an issue... Got home and checked the brake rotors at all 4 corners and the other 3 were in the 70-80 degree range... Right rear was 600. Anybody want to fry an egg real quick???

I tore into it after lunch and found the slider pins with some rust on them in the exposed area between where they screw into the caliper/brake pad holding assembly and the holes they slide through. I took them out and cleaned them off, polished them to a mirror finish on my buffing wheels, and set them aside. I figured I might as well take a look at other areas where things might be binding up so I removed the pads and put some high-temp grease on the locations where they slid against the caliper assembly, checked the caliper piston to ensure it was moving freely by having one of the kids pump the brake while I held the caliper in my hand, and then went the other way with it using a clamp to push it back in (after cracking open the bleeder screw to let some fluid out and not force it back through the ABS pump assembly and other things).

Upon reassembly I also put some high temp grease on the slider pins to hopefully ensure they didn't rust again, tightened everything up, and went for a 4-mile roundtrip drive to get some diesel. Now, I'm sure the pads were not in the exact same wear grooves as they were before I removed/reassembled them, so maybe that is the reason they warmed up again, but when I checked the temps of the rotors when I got home the other 3 were in the 80's and the right rear was in the 120 range...

When I turn the wheel/tire assembly by hand on that side, it doesn't feel any different than the opposite side wheel. Heck, it didn't when I first jacked it up to check it. It didn't really *feel* like it was dragging, but it obviously was with that much heat in it after a 15-minute drive this morning to/from church. Also, I noticed that the brake pads don't seem to retract any at all from the rotors on that side. They obviously aren't putting *pressure* on the rotor as I can turn the wheel easily, but still...

FWIW, I've changed brakes/rotors on several other Dodge products, some Chevies, a Mazda, and a newer Jetta TDI, and from what I remember there always seems to be a thousandth or so gap between the pads and the rotor once the brake pedal was released, but it doesn't seem like this one is doing it. When the piston is extended from the caliper upon depressing the pedal, it definitely pushes the pad into the rotor, but it just doesn't seem like it's retracting from it like it should. Is that an issue with the caliper piston, possibly? I ran it through 1/2" or so of travel and it didn't seem to bind up any, fwiw.

Thanks for any help anybody can provide.

hkpierce
02-10-2014, 04:19 PM
Flushed recently? Do you use your hand brake - if so it is not uncommon for the cable to hang up where the cables split.

rob99rt
02-10-2014, 05:25 PM
Flushed recently? Do you use your hand brake - if so it is not uncommon for the cable to hang up where the cables split.

Entire brake system was flushed last year when I changed out the caliper, so it's in good shape. We don't brake much, either, and the fluid reservoir is still topped off at nearly the same level as it was last year when I flushed it. As far as the hand brake goes, it's not that either. Since it stuck a couple years ago we never use it, and the inner "hat" part of the rotor isn't nearly as hot as the rim where the brake pads contact it.

FWIW, I just came back from a 7 mile drive and the rotor was 380 degrees while the other side was 61. Since all slider/pad contact points with the caliper apparatus were lubed with high-temp grease and seemed to be moving well when I buttoned it back up yesterday, I can only assume the piston is having an issue and is continuing to press against the rotor when when the brake is released. That would confirm what I saw yesterday with pads not retracting back at all from the rotor when the pedal was released...

I also replaced the last section of rubber line last year, too, that goes into the caliper, so I doubt that's a problem since it's new.

Now I just have to figure out what kind of caliper it is again.. Bosch, AT... whatever, or the 3rd one... frustrating...

According to the brakechart.pdf file posted in another thread, I've got the ATE units.

Aqua Puttana
02-10-2014, 06:05 PM
Did the pads look glazed? Do the rotor surfaces themselves show signs of overheating?

Last summer I had a parking brake shoe dragging enough to heat the rear brake assembly. Funny thing was that it seemed to rotate fine by hand. I had just changed the rear axle bearing and seal before that and all seemed fine for quite a few drives. The heat showed later. :idunno:

As I was on a road trip I just backed off the adjustment a bit and all was well. You might double check the parking brake. It may not be the service brakes at all.

vic

rob99rt
02-10-2014, 11:53 PM
Did the pads look glazed? Do the rotor surfaces themselves show signs of overheating?

Last summer I had a parking brake shoe dragging enough to heat the rear brake assembly. Funny thing was that it seemed to rotate fine by hand. I had just changed the rear axle bearing and seal before that and all seemed fine for quite a few drives. The heat showed later. :idunno:

As I was on a road trip I just backed off the adjustment a bit and all was well. You might double check the parking brake. It may not be the service brakes at all.

vic

Pads didn't look to be glazed and the rotors were still fine (no discoloration, micro-cracks, etc.). I think I caught it fairly early this time around, too.

I had hoped it was just the parking brake shoe dragging, but that's not the case from what I can tell. The inner part of the rotor (hub section) is a bit cooler than the outer edge and the wheel itself would be toasty if it was the hub/drum section of the rotor hat, I think. I've checked the caliper itself with the thermometer and it was a couple hundred degrees this morning, too, from the heat transferred from the rotor.

Just hope the next caliper lasts a bit longer than the last one. 14 months or so for an aftermarket caliper (only about 16K mostly highway miles) is pretty lousy.

sailquik
02-11-2014, 12:47 AM
Glad you mentioned the probable "real" cause of all your brake problems!
Simple....unless you are a very skilled machinist, with all the tools (a CMM would be good here) your replacement (with aftermarket "sort of the same parts) of your original genuine Mercedes Benz brake parts very well may be the whole issue.
Buy the correct Mercedes Benz parts (traceable to your VIN # from the OEM factory installation), at an authorized Mercedes Benz Sprinter dealer (commercial....if you can find one) and I would be willing to bet that your brake issues will go away.
Actually you probably would have never have had any brake issues had you simply replaced the original pads/rotors/E brake parts with
genuine MB replacement parts specific to your Sprinter's VIN #.
Did you also replace the rotors with aftermarket?
Save a few $$ up front......pay a lot more later! Plus a lot of headaches for the last 18 months it seems.
Roger

lindenengineering
02-11-2014, 02:47 AM
Glad you mentioned the probable "real" cause of all your brake problems!
Simple....unless you are a very skilled machinist, with all the tools (a CMM would be good here) your replacement (with aftermarket "sort of the same parts) of your original genuine Mercedes Benz brake parts very well may be the whole issue.
Buy the correct Mercedes Benz parts (traceable to your VIN # from the OEM factory installation), at an authorized Mercedes Benz Sprinter dealer (commercial....if you can find one) and I would be willing to bet that your brake issues will go away.
Actually you probably would have never have had any brake issues had you simply replaced the original pads/rotors/E brake parts with
genuine MB replacement parts specific to your Sprinter's VIN #.
Did you also replace the rotors with aftermarket?
Save a few $$ up front......pay a lot more later! Plus a lot of headaches for the last 18 months it seems.
Roger

I "Roger" this Roger!
I steer clear of many aftermarket parts on MB's--It leads to comebacks and early failures in most cases.

In all these instances I sight the saga of the Dodge Cummins water pump!--Customer rejected the $550 genuine factory pump made in the USA in preference to the Napa made in China pump $99.99; I kid you not! He insisted upon it!
Thats when Linden Engineering and a 2001 Dodge Ram Pu got married!--and we had a re-occuring encounter every 800 miles or 5 weeks--it was like a womens period! Failed regularly as a Swiss clock that cuckoo'd!--- 'cos I felt like the bloody cuckoo!
OK Napa replaced it FOC each and every time--But my business ate the labor!
No fewer than 5 times did we labor the ponderous task!:thumbdown:

But then it was divorce time!
In the yard was a take out engine-- "Blown"-- with an amost new original water pump on it!
It got installed and the divorce was "Nisi'!
Of course like divorce & matrimony some cheating was an oft' ingedient! I never told him (owner) the pump was used--But then he never asked!
I still see it from time to time; owner happy as a pig in poop wih his supposed Chinese water pump!:thumbup::lol:
Cheers Dennis

Dingo
02-12-2014, 09:51 PM
Does your handbrake "feel funny " when you release or apply it ?
I had exactly the same problem on several vans , it always came down to the qcompensator under the van seizing on du to dirt & rust build up . Mine has been hammered apart & wire brushed & now wears a deep coat of heavy grease on every part of the moving parts .

It held the handbrake shoes on one side against the brake disc & really warmed things up , Once i had freed off the compensator all was well underneath my van .

Boater
02-13-2014, 12:49 AM
Just concentrating on the piston not backing out issue, is it at all possible that a piece of dirt, grit or rust got into the port before/as you screwed the hose union into it?

Just thinking, a lot of hydraulic pressure available to push the piston out over a bit of grit (probably scoring a groove in piston and caliper) but very little pressure pushing it back in again. I wouldn't ignore the advice about using quality parts, calipers are not rocket science, but do require medical grade cleanliness during assembly/fitting/repair - it might even be a bit of factory swarf if the cheap copy is not checked or assembled in suitably clean conditions.....
On the other hand with care and cleanliness the originals can be rebuilt (if not scored) with new seals and calipers.