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So I got my front brakes done, rotors and pads, from this shop and they had dropped a piston out of each caliper, they said they got them back in the caliper and was able to finish the job. Well they set off the sbc module red brake message. After bleeding the calipers, and a few pumps of the brake pedal with the engine on, the message went away. It has not returned and the car seems to be braking just fine like normal. Do you think I'm okay? I was thinking of doing a brake flush and call it good.
However the dealer is saying I should replace both front calipers as they have lost thier braking integrity, that the piston seals or boots can tear and overtime cause issues. The pistons work fine though. What do you think? I was thinking if there was any pressure loss or air/moisture in the system, the red brake message would reappear?
Lastly how many pistons do the calipers have?
Thanks!
Last edited by sunnybenz45; 12-10-2019 at 09:53 PM.
I wouldn't worry about the caliper, it should be fine. Could be different one these calipers but from my experience the piston is held in with a square cut gasket and then there's just a rubber dust boot.
Id probably get a brake flush with someone who has star to do it properly.
So I got my front brakes done, rotors and pads, from this shop and they had dropped a piston out of each caliper, they said they got them back in the caliper and was able to finish the job. Well they set off the sbc module red brake message. After bleeding the calipers, and a few pumps of the brake pedal with the engine on, the message went away. It has not returned and the car seems to be braking just fine like normal. Do you think I'm okay? I was thinking of doing a brake flush and call it good.
However the dealer is saying I should replace both front calipers as they have lost thier braking integrity, that the piston seals or boots can tear and overtime cause issues. The pistons work fine though. What do you think? I was thinking if there was any pressure loss or air/moisture in the system, the red brake message would reappear?
Lastly how many pistons do the calipers have?
Thanks!
The issue is that the seal integrity has been compromised, so you might have leaks in the future. This shop was not competent to work on the car since they obviously had no idea of the special mode you must invoke to change pads on an SBC car. If it were my car, I'd have the calipers rebuilt or replaced. The shop should pay for it.
The square seal should be ok as long as they lubricated the piston and put it back in carefully. The dust boot should also be fine if they put it back on carefully. The issue is that they are delicate and if they ripped the boot at all or it isn't seated correctly then you will get dust and moisture in there which will speed up corrosion considerably. However that isn't likely to be an issue for many years. Hopefully they bled the system properly...
Front calipers have 8 pistons. Back have 4 I believe.
The issue is that the seal integrity has been compromised, so you might have leaks in the future. This shop was not competent to work on the car since they obviously had no idea of the special mode you must invoke to change pads on an SBC car. If it were my car, I'd have the calipers rebuilt or replaced. The shop should pay for it.
is the special mode you have to invoke unplugging the sbc plug? xD
is the special mode you have to invoke unplugging the sbc plug? xD
There are several not-so-smart ways to deactivate Sensotronic. That's one (it will probably generate all kinds of codes). Waiting for the CAN to go to sleep and hoping nobody opens a door is another. The pro way is to deactivate it with a decent scan tool.
Hopefully, when the piston were dropped out of the caliper, they didn't get scratched. And were properly cleaned before reinstall.
If not the scratched piston will eventually tear up the seal, which will leak over time, allowing moisture and corrosion of that piston to set in.
That's why you should only take your car to a reputable shop, and they should have a Star Diagnostic Computer.
As some systems on a Mercedes can only be access via Star. I'm just glad that your tech didn't injure himself with the SBC.
Also I will cut you some slack, not knowing about your car because your a newbie.
OP, read and understand the systems on your car. Pages 42-55 deal with deactivation, activation, and bleeding of the SBC system. It explicitly states to activate and pressurize the system before the engine is started.
So I got my front brakes done, rotors and pads, from this shop and they had dropped a piston out of each caliper, they said they got them back in the caliper and was able to finish the job.
Pistons can't just drop out of the caliper. The dust boots, and seals hold them in. This is what happened; the SBC system activated with the calipers removed, and blew a piston out of each caliper, which dropped the pressure so no more pistons blew out.
The two pistons bounced on the shop floor. Use your imagination on the damage. Brake fluid blew everywhere, possibly even your paint, making a real mess. They probably sanded the damaged pistons enough to get them back into the caliper bores, and threw it back together. Yeah, I would say they are compromised. Replacement/rebuilt front calipers? Just try finding a pair of those!
Getting yours rebuilt by someone that really knows what they are doing, is the best bet, Hope the pistons can be saved. Sorry that happen to you.
Minor thread jack. I recently did the brakes on the mr2. Below you can see the kind of corrosion you get when the dust seal isn't working the best. It will damage the square seal edge but generally the brake fluid keeps the inner portion clear and clean. Of course any surface damage at all to that area on the piston will cause issues.
Clean on the inside of the bore past where the seal sits, corrosion on the outside under the dust boot.
I replaced all of them, luckily less than one E55 caliper's worth of pistons for the whole car.
I am currently working with the shop to get the front calipers replaced. Although this shop has been a pain in the rear, as they are denying responsibility.
There are several not-so-smart ways to deactivate Sensotronic. That's one (it will probably generate all kinds of codes). Waiting for the CAN to go to sleep and hoping nobody opens a door is another. The pro way is to deactivate it with a decent scan tool.
This is off topic but WHY do SO MANY grown men start a sentence with the word SO???????
That is really off topic, but it bothers me too. I remember not long ago people started a response with "basically"
Back to the brakes. When picking a shop to perform service on a your Mercedes, they need to be properly researched, and checked out. I mean any level of service, and repair! If cost is your number one priority, you own the wrong car.
My one owner E55, that I have had for for year, had wonderful care, and service from the original owner, even though the mileage was 127K at time of purchase. 5 page VMI, of regular service at a higher end Mercedes dealer.
Not really concerned with my grammer lol but thank you all for valuable knowledge and opinions.
I'm not concerned about you not being concerned: just pointing out a fact that occurs on such a regular basis it's hard to keep ignoring. I'll keep working on it at therapy though okay?
I'm not concerned about you not being concerned: just pointing out a fact that occurs on such a regular basis it's hard to keep ignoring. I'll keep working on it at therapy though okay?
Why not just do the work yourself!? Why pay someone to do such a simple job when you can save yourself more than $1,000 and if you go through FCPEURO the parts are warrantied for life!!!
12-10-2019, 09:41 PM
