Hello MB World. In Feb I got my wife out of the way with the purchase of a 2015 GL.

Now I'm ready to buy my dream car.

I've been looking at a few 2009 or 2011 SL550's.

I've noticed that if the ABS Pump has been replaced you can get these cars with the mileage between 60k-80k mi. around 24-27k. I only look at the cars where the replacement was done at a Mercedes Dealer.


My question. Once the pump is replaced have you had any other ABS problems. Is it worth buying now that the ABS pump has been replaced.

Thanks.

 

What does the ABS/SBC have to do with it? They have a finite lifespan, the replacements will last about as long as the original.

 

You kind of answered my question. If it should last as long as the original I can expect it to not to be a problem with flushing the brake fluid.

I was asking because I don't want this to be a problem 20k miles from now. I've had some bad experiences with other cars when major work is done.

Thanks.

 

Has nothing to do with the brake fluid. They fail after a number of activations, there is a reason that MB stopped using the system on most cars. It's an unreasonable maintenance item.

 

Beyond all the typical MBZ maintenance concerns, there are four "complexities" to consider on the R230: SBC, ABC, BCM, PSE and the Vario Roof.

SBC = Sensatronic Brake Control. This uses an electric pump instead of a vacuum booster to provide braking assistance. The pump motor has a finite lifespan and will start giving you warning when it reaches a certain number of cycles. The pump does not run for each brake pedal press. It runs periodically to keep the brake fluid pressure charged. Obviously more braking = more pump cycles, but most cars go well over 100k before needing the SBC pump motor replaced.

ABC = Active Body Control which is a high-pressure hydraulic system that controls the suspension. It can individually adjust the height of the four shocks, keeping the car level in turns, lower at high speeds, and even allowing it to be raised for clearing speed bumps and rough roads. The hydraulic pump, hoses, valve blocks, shocks, dampeners and accumulators are all subject to wear and tear and will need maintenance over time. A catastrophic loss in fluid can cause the car to totally "sit down" and if the front wheels are not straight, they can impact the fenders. There was a slight redeisng to the system for MY2007 that may have made it more reliable and require less frequent maintenance.

BCM = Battery Control Module. Because the SB system uses an electric pump, it requires voltage to operate. If the SBC pump has no power, you pretty much have the brakes of a covered wagon. Because of this, the car uses two batteries. One under the hood only for starting the engine, and one in the trunk for all other electrical "consumers". The BCM manages these two batteries to keep them charged, and can switch in the starter battery to supplement a weak consumer battery (but not vice-versa). These cars have many electrical consumers that draw current even with the ignition switched off, so a weak consumer battery can be a problem on cars not driven daily. Also, the BCM has some extra fuses that can cause issues if blown and needs a bit of extra TLC when changing batteries.

PSE = Pneumatic System Equipment. Several components are operated pneumatically instead of electrically. These include the door locks, various locks on interior storage compartments, the multi-contour seats, and the trunk latch, Leaks in the air hoses can cause these components not to operate. It can also cause the PSE pump (mounted int he trunk) to overheat and fail.

Vario Roof = The retractable hardtop. This uses a hydraulic pump in the trunk to operate a series of 8 cylinders, 13 limit switches, and an electric motor. Over time, cylinders will leak an limit switches will fail. The pump can also fail. The good news is that there is no canvas to rot, and there are some really good diagnostic resources as well as sources for rebuilt cylinders.

 

Thanks for breaking that down. I was referring to the ABC system. Not ABS. My fault.

 

I suspected that you were talking about ABC, although SBC (which operates ABS) is a concern, too. Are you a DIYer or are you going to rely on a mechanic to do the work? If you DIY, and have the tools and skills and are willing to invest in a copy of Star Diagnosis, then none of these things is really that bad. There are a few parts that may be in the $1,000 range, but most are not. if you are going to rely on a mechanic, then make sure you are prepared - few ABC repairs at a shop will be under $2K. Dealers will charge MUCH more.

 

I've got a local guy who has his own shop. He used to work at the Mercedes dealer.

Really appreciate the breakdown.

Would you buy a car where the ABC was recently replaced.

Can I look forward to not having any immediate problems with it.
​​​​​​

 

I don't think having the pump replaced recently would sway me one way or another. The pump usually lasts more than 60K-80K miles, especially the MY2007 revised version. Now, what will kill a pump is running it dry of fluid. And that is usually caused by a leak AND the driver ignoring the red "ABC - Stop Engine Now!" warning. There have been some recent reports int he forums of leaks in the main pressure hose on the revised MY2007+ system (it happened to me). I speculate they had a bad batch of hoses. So, it's possible that one of the 2009/2011 cars you are looking at with with low (60K-80K) miles and a new pump had the main hose blow, the driver ignored the warnings and fried the pump. If that's what happened, then no big deal.

If you find a car in the range with the original pump, then no big deal either, as there just aren't rampant reports of pump failure. Read the forums and you won't see too many reports of bad pumps. Most problems are bad dampeners and accumulators and (internally) leaky valve blocks that let the car sag when stopped. Of course there are no guarantees. You can always buy the "perfect" car that has had no problems, or has a new pump and other parts, and something can still fail tomorrow.

 

Thanks for the reply. I'm going to definitely take a look at them. I'll post picks when I buy.