Another SBC Story....

[karozza]

YOM 2002 & definitely on the original SBC. Now just covered over 26600 miles.

So, I am just about to start enjoying the last day of my mini holiday touring eastern Sicily & about to drive out of the gate from the B&B when I hear a sudden thump(similar to hitting the car's undercarriage on a ramp) as soon as I hit the brake pedal; then, no brakes :fail

Warning lights in RED in both displays & beeps galore; I stopped breathing Where, you might ask, in Trecasgni at an elevation just tipping 1900ft; all down hill with no brakes The previous day did a lot of driving up & down & lots of fog.

First things first, warning lights, as I can recall as I was still in shock(I couldn't breath; remember!), right display kept stating Reduced Brake Effect, Visit Workshop! Left display:STOP-Brake Defective but also, kept showing ESP failure after switching ignition on.

Anyways, started breathing again & managed to get to a Petrol Station with extreme caution, filled up tank. As I started making phone calls, after parked at the side, I switched ignition on, heard the usual noise from the SBC pump; everything back to normal!!!!

I then drove carefully the 2 hour plus drive back to the ferry, visiting some towns on the way; all good. Got back to Malta & even did some sudden but not extreme braking; all good.

Now, will be taking it on STAR.

Is it normal for SBC to fail & then come back in service; does this mean a replacement is needed??

 

[MancMike]

That sounds pretty frightening. I had total brake loss in a previous car, so know the feeling.

For future reference though, Mercs with SBC still have brakes without SBC, but you'd have to press damn hard on them to stop the car, as they're unaided, but if you've ever driven anything without a master cylinder, like something particularly old, or an Ariel Atom then you'll know what unaided brakes feels like.

 

[lxi]

I had the same error messages on my first SL - the day after I got it.

Long story short, the SBC pump was fine - I kept the car another 3 years - the problem was the consumer battery in the boot was knackered and when this happened I was using a lot of things (lights, heated seat etc) which unfortunately delivered the coup de grâce.

It was trailered away, they said it had missed an upgrade for the alternator (!!), replaced the battery & it ran perfectly from there on.

 

[karozza]

I had the same error messages on my first SL - the day after I got it. Long story short, the SBC pump was fine - I kept the car another 3 years - the problem was the consumer battery in the boot was knackered and when this happened I was using a lot of things (lights, heated seat etc) which unfortunately delivered the coup de grâce. It was trailered away, they said it had missed an upgrade for the alternator (!!), replaced the battery & it ran perfectly from there on.

This is why I'm curious if this is an electrical issue as the ESP came on at the same time. AFAIK, when I read about expired SBC lifespan, it normally fails & doesn't function anymore...& not come back to life....but I might not be accurate!?

 

[HB]

At 26k the SBC should be totally fine. My eclass one bit the bullet at 150k. Most likely a battery issue.

 

[lxi]

This is why I'm curious if this is an electrical issue as the ESP came on at the same time. AFAIK, when I read about expired SBC lifespan, it normally fails & doesn't function anymore...& not come back to life....but I might not be accurate!?

From memory, the progressive shutdown started with ESP, then Comand, then brake (grey) warning, ending with brake red warning (which did get my attention).

I'd be fairly confident it's a battery issue

 

[karozza]

I hope so! As I'll just go out & buy another battery...

On the other hand, I had just started the car, maneuvered around in the parking, not even switched on the lights & all the warnings came at once slowly coming out of the ramp/gate. To my knowledge, the ESP came up with the other warning faults all in red after I had shutdown & started again a few times.

 

[lxi]

When you buy a replacement, make sure it's the proper AGM type

 

[Dryce]

When you buy a replacement, make sure it's the proper AGM type

..... why?

My feeling when dealing with the last battery I had to replace (which was AGM) was that the benefits were intangible whereas the price differential was definitely tangible.

So I just went with the S5 battery Bosch recommended for my MB - which was a lot cheaper (at the time) from Costco or Eurocarparts.

 

[merc85]

..... why?

My feeling when dealing with the last battery I had to replace (which was AGM) was that the benefits were intangible whereas the price differential was definitely tangible.

So I just went with the S5 battery Bosch recommended for my MB - which was a lot cheaper (at the time) from Costco or Eurocarparts.

The oem ones i believe are Gel sealed, the Aftermarket ones are lead acid and ive heard can expel vapour.

Saying that i have fitted a lead acid one myself see my project thread and haven't as yet had any issues as of yet.

 

[karozza]

If I do replace the battery, it will be a silver Varta that is appropriate for the car. These carry a 3 year warranty.

 

[Dryce]

The oem ones i believe are Gel sealed, the Aftermarket ones are lead acid and ive heard can expel vapour.

Good point.

My W211 came with an AGM battery but there was still a vent tube for non AGM.

 

[karozza]

So, went & checked it on STAR & apparently the SBC has not expired!



Diagnosis shows fault in rear left & right pressure regulators as a result of hydraulic pressure loss. It also states to replace hydraulic fluid & bleed first; if problem persists, replace SBC. I have booked the car for brake hydraulic replacement as I have no idea when this was done last.

Has anyone had the same experience; any suggestions??

 

[guydewdney]

There was an incident where someone was advised to replace the sbc, but turned out to be a very minor leak in the hard brake line, found by his local mechanic and missed by two merc specialists. Similar story?

 

[karozza]

There was an incident where someone was advised to replace the sbc, but turned out to be a very minor leak in the hard brake line, found by his local mechanic and missed by two merc specialists. Similar story?

Yes, I have read this also & asked him but he said this doesn't apply at the rear as it ends there

Anyway, I will have a look with him when replacing the brake fluid.

 

[karozza]

Well, I've driven over the weekend & used sudden braking a couple of times(to avoid some **** driving into me) & so far all is well.

Has anyone had experience with losing brakes as described in the original post & then come back to normal!?

 

[karozza]

Apparently no one

 

[karozza]

Well, I took the SL in today to have the brake fluid replaced. Up till now, had no faults whatsoever. Picked up the car, all good, drove maybe 5KM down the road to my shop, parked the car & switched off. after 5-10 minutes went back to the car & started the engine; again, a bundle of warnings including the continuous beeping from the both displays :fail

Apart from Brake Defective. Stop Vehicle! got: Incr. braking distance Start Engine! Also ABS light stayed on

This time though I drove the car in to the shop & the brakes were still working

The engine felt like it was hunting & running slightly erratically in drive with the brakes & even in Park at one point.

Any assistance will be really appreciated.

 

[lxi]

Well, I took the SL in today to have the brake fluid replaced. Up till now, had no faults whatsoever. Picked up the car, all good, drove maybe 5KM down the road to my shop, parked the car & switched off. after 5-10 minutes went back to the car & started the engine; again, a bundle of warnings including the continuous beeping from the both displays :fail

Apart from Brake Defective. Stop Vehicle! got: Incr. braking distance Start Engine! Also ABS light stayed on

This time though I drove the car in to the shop & the brakes were still working

The engine felt like it was hunting & running slightly erratically in drive with the brakes & even in Park at one point.

Any assistance will be really appreciated.

See post #3 & #6.

 

[karozza]

Ixi, you think it's the consumer battery?? I'm a bit confused as there were no faults shown on STAR