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W460 sticking caliper piston?

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reinhardtius
Posts: 796

W460 sticking caliper piston?

Post#1 » Wed Oct 07, 2009 5:48 pm

I've managed to fix almost all of the problems on my G Wagen except for this new problem that recently started happening after driving the G over 700 miles. I started my journey in MD and drove to Richmond where I stayed there a few days, but when I left Richmond I got on the highway and I was unable to go above 50MPH, no matter how hard I pushed on the pedal. I got off an exit and conveintly it was wet and a red light was ahead. It being a quiet intersection I slammed on the brakes to make sure they weren't getting stuck. I powerslid about 70 feet and stopped a few feet before the white line. I continued onward and the brakes did not stick again for the remainder of the drive down to NC and back.

When I got back home to MD I drove the G to work and I was unable to get above 50 MPH again. When driving up hills I literally had to downshift into the lowest of gears (all the way down to 2nd on a hill I usually climb in 4th gear) I did pull over and poured water on the calipers and rotors and they steamed quite a bit, and continued onward, but they still seemed to get stuck.

What might be wrong with my brakes? Or is it driveline related? Differential related? Transfer case related? Not too sure what is wrong, but would like to fix it for the future buyer of the G and for myself if I decide to keep the bugger :P

Please help!

User avatar
inkblotz
Posts: 7138

Re: W460 sticking caliper piston?

Post#2 » Thu Oct 08, 2009 4:07 am

How did you determine it was brakes? After driving awhile get out and put your hand on each wheel feeling for heat. If a caliper is sticking it will be very hot to the touch. That said if one caliper is sticking the G will be pulling one way or another. Another option if it is brakes is that the hand brake cables are corroded internally and will not release fully. And along that same line the adjusters at each wheel could be corroded as well. Jack up the G. release the parking brake chock the tires that are down and free spin each tire. If you don't feel any resistance than more than likely it is not brake related. I had the rear drum drag due to bad cables replace the cable and off she went.

From what you describe I am not 100% convinced it is brakes though.

Mark

User avatar
reinhardtius
Posts: 796

Re: W460 sticking caliper piston?

Post#3 » Thu Oct 08, 2009 5:09 am

inkblotz wrote:How did you determine it was brakes? After driving awhile get out and put your hand on each wheel feeling for heat. If a caliper is sticking it will be very hot to the touch. That said if one caliper is sticking the G will be pulling one way or another. Another option if it is brakes is that the hand brake cables are corroded internally and will not release fully. And along that same line the adjusters at each wheel could be corroded as well. Jack up the G. release the parking brake chock the tires that are down and free spin each tire. If you don't feel any resistance than more than likely it is not brake related. I had the rear drum drag due to bad cables replace the cable and off she went.

From what you describe I am not 100% convinced it is brakes though.

Mark


I agree

Just food for thought. Back in April when I blew a head gasket we were driving it back through Philly back to my apartment and the rear drums got stuck and were literally smoking - not sure if this is the return of the sticking rear drums? For what it's worth I know for a fact there is not a proportioning spring in the back so I'm sure that could possibly have something to do with it. I'm not set on it being just the front brakes. Sure, if you pour water on brakes they are going to smoke, but I suppose it could be the rear drums?

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Gelande
Posts: 4733

Re: W460 sticking caliper piston?

Post#4 » Thu Oct 08, 2009 8:47 am

if anything with the spring missing, its the other way around.

When you lift the truck, and have no spring, or the wrong bias spring, then you are putting barely any brake bias to the rear, thus when you need to slow down a lot, and you don't have correct rear brake pressure, you are pushing the fronts too hard.

This is not only an unsafe brake condition, but also can cause the brakes to overheat and fail from heat.

User avatar
reinhardtius
Posts: 796

Re: W460 sticking caliper piston?

Post#5 » Fri Oct 09, 2009 8:07 am

mserpe wrote:if anything with the spring missing, its the other way around.

When you lift the truck, and have no spring, or the wrong bias spring, then you are putting barely any brake bias to the rear, thus when you need to slow down a lot, and you don't have correct rear brake pressure, you are pushing the fronts too hard.

This is not only an unsafe brake condition, but also can cause the brakes to overheat and fail from heat.


Do you think it could be the emergency brake getting stuck?

User avatar
reinhardtius
Posts: 796

Re: W460 sticking caliper piston?

Post#6 » Tue Oct 20, 2009 7:30 am

UPDATE - We spent 6 hours trying to get my G Wagen out of the garage. The right (passenger) rear wheel would not budge and I also noticed the E brake level was harder to pull up. It had sat for 3 weeks mind you. We finally got it out with a wheel lift tow truck and then from there I drove it up the driveway with the rear wheel dragging. Once I got up to the street the rear wheel broke free. My question is: is the Emergency brake only on the right side? Any other ideas? We now know it's in the right rear, not in the front.

Thoughts? Please help

Hunter

User avatar
inkblotz
Posts: 7138

Re: W460 sticking caliper piston?

Post#7 » Tue Oct 20, 2009 9:04 am

I am still leaning toward the brake cable (the E brake is on both rear wheels) and the right side cable sounds like it is binding. I would take the right drum brake set-up apart, and R&R the hand brake cables.

You may be able to run one more test prior to doing this. Get the G rolling smoothly but when you park it do not apply the hand brake in fact remove the nut that holds the right brake cable in place (at the base of the E-Brake handle).

If after this the right rear still locks up than you can probably eliminate the brake cable. and move on to the drum brake cylinder at that wheel.

M

User avatar
reinhardtius
Posts: 796

Re: W460 sticking caliper piston?

Post#8 » Tue Oct 20, 2009 9:42 am

Thanks, Mark. You're the man. I'll relay this to the mechanic if it's any help to him.

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