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Tuesday
Mar102015

Sensotronic Brake Control

If you remember with the launch of the SL in 2002, and then the higher versions of the E Class, Mercedes-Benz introduced Sensotronic Brake Control (SBC). A revolutionnary braking system with a pump, and pressure reservoir to enhance braking, on the premise that most folks would never apply the level of pressure even with a power brake to shorten brake distances.

In 2003 the E500 had SBC brakes, and an air suspension. Neither of these are inexpensive systems to repair.

In the case of Walter, when lining up for an apex, SBC does a phenomenal job to scrub off speed in a short distance. Brake in a straight line and hit the apex...Walter never misses a beat.

The downside of SBC brakes is that they are complex to service, even performing a brake job (replacing pads) is an undertaking the brake system needs to be de activated with the DAS. Bleeding the brakes is an experience in its own. Not surprising Mercedes discontinued SBC brakes after a few years.

Some weeks ago Walter decides to get cranky, lights up the dash in red, yes the SBC pump is acting up. The car still brakes but in a different fashion that when the pump is working. If you have a car with SBC brakes and the dash lights up red, be very cautious, there is a reason its red and it does not go away.

Keep in mind that you are used to braking with increased pressure from the pump. The messages in the dash bluntly tell you what the car will do - reduced braking effect - longer braking distances. Not recommended to drive the car.

Its an older car, it fell in love with flat beds last year, to start 2015 its the SBC pump. A perfect OUCH moment of nothing will be inexpensive to repair.

Bring the car to a Mercedes-Benz dealer the warranty on the SBC system has been extended to 15 years, from the previous 10 years. In our case Walter is out of the 10 year time frame.

Yes...there is a silver lining in the SBC brake cloud.

 

 

Tuesday
Jan062015

Update for 2014

At times cars have a craving for attention and Walter in 2014 turned into an extreme attention seeker.

Not only seeking attention, but having perfect timing in seeking epic care at the most inopportune times. Knowing that a car (Walter) was not high on the priority list at that specific moment.

In 2014 Walter acquired a taste for flatbed tow trucks. Although being stranded is part of the Benz DNA, Walter expressed his true colors, character, and upheld the German tradition.

1- In early January, an auspicious start to the year, Walter elects to squat down on its rear suspension, and remain down. A great way to go for a ride on a flatbed, and get a new air pump for the suspension.

2- In June Walter decides to become a total nuisance, make a scene at a busy intersection on a Sunday morning. Obvious go for another ride on a flatbed, for a new ignition crank sensor.

3- A few weeks ago in December, Walter decides its time to go for another flatbed ride. What better way than to have the belt tensioner fail, at a choice moment.

Yes...its absolutely fair to say that Walter is an undisputed flatbed hero. Testing patience, understanding, and making sure that its always done at a time when priorities are disrupted.

If Walter could speak, the conversation would go like this...

Walter: You are trying to crank me up to 200K, watch me act up, get obtuse, and really show my Teutonic colors.

Colonel: I don't need to crank you up to 200K, you are very lucky that every time you become a flat bed drama queen I have other priorities than take you to the back field and deal with your Benz DNA.

Walter: Still suckered you into an axle, a windshield, maintenance, brakes pads, and I probably forgot some stuff.

Colonel: You sure did, you are aware that I hate cars that get too needy.

Walter: I love getting flat bedded to the friendly mechanic.

Colonel: Sure you do, and its not free. The friendly mechanic does not pay me, I pay him.

Walter: When I'm there he treats me good, and you like royalty when you show up. He does not pay you?

Colonel: No...I pay him to fix you, and take care of you...I repeat I pay him.

Walter: OOPS...you never ask how much it will be, I thought he payed you. I was helping you make money.

 

 

Tuesday
Dec232014

The Belt Tensioner

It must be normal practice that a car will aggravate you at the most inauspicious time. Its usually the way these events develop.

Last Friday with a myriad of things going on at the same time, and on a trip towards a place of business obvious that the serpentine belt tensioner elects to fail.

Here is the deal:

Entering an highway on ramp Walter is suddenly hard to steer. "What is wrong with the steering?" "What happened to the power steering?". Put some muscle into the steering wheel to negotiate the almost circular on ramp.

A quick look at the dash, which now is glowing red with "Electrical Consumer...visit workshop"

Utter disbelief, who needs this right now? Not me...not a single abnormal sound from the car.

By now on the highway, still no power steering, and the electrical consumer is on...this is not good.

A glance at the temperature gauge which is no longer at 80 and creeping towards 95 confirms that the water pump is no longer turning.

Yes...the serpentine belt is off with no power steering, alternator, and water pump.

Fortunately coming up to a service center, take the exit, park the car, open the hood, to confirm that the serpentine belt although still in place is very loose with no tension.

Now its back to...really don't need this s%&t this morning.

Let's call CAA this car is not going anywhere by itself. A quick note that CAA is extremely professional, understanding, with text message confirmations. If you don't have a CAA membership, get one its priceless when you need them.

A call to the friendly mechanic "The belt tensioner just let go, sending you the car on a flatbed".

Another call to get a ride "Please come get me at...."

Being philosophical it could have been worse, its just a car, good thing that CAA is very helpful, nothing money can't fix.

One more thing...whoever designed that tensioner hopefully got a promotion for the cost saving inititiatives.

 

 

Tuesday
Oct072014

Brake Lines

At times cars have this innate ability to totally irritate you. Walter as you can see from the latest posts is on a mission to become an irritant, starting with the suspension air pump, crank sensor, windshield, then the wheel alignment, and a few days ago a brake line.

Lets step back for a moment.

There was an hydraulic fluid leak in front of the left rear wheel. At first blush it could be the shock absorber which has hydraulic fluid, that started to leak.

Not a big deal, but a constant minor leak. 

Peaking under the car during the wheel alignment the left rear shock is very dry...oops does not seem to be the shock abosorber. 

If its not the shock abosorber, the other possibility is a brake line. It almost does not make sense that a brake line would leak (seep)...or does it?

Until the "brake fluid low visit workshop" comes on in the dash at the most inopportune time. A case of "I don't need this s$%t this morning" 

If you see some sort of hydraulic fluid leaking/seeping from the car, got to a workshop immediately and have the leak confirmed and repaired.

Been around Benzes for decades, we keep on driving Walter, even when it was not the shock we still drive Walter, even when the lights in the dash come on, we still drive Walter. 

Hydraulic leak, low brake fluid, how much is left in the master cylinder? 

Walter makes it on its own to the friendly mechanic. Yes...drove Walter in a very cautious fashion to minize brake applications.

The conversation goes as follows.

"A brake line is leaking in front of the left rear wheel" reply from the mechanic "You should not have driven the car...not safe"

"How could a brake line leak?" reply from the mechanic "SBC brakes generate very high line pressures the metal fatigues cracks, leaks". It all makes a ton of sense on a 12 year old car.

From the mechanic "You know that its a pain to bleed the lines with SBC brakes...you remember" the reply "Yes...and it consumes a ton of brake fluid too...I don't think its bad that too much air went in the system".

Fortunately we have other vehicles...and the patience to endure Walter's foibles.

Hopefully whoever engineered those weak brake lines from over a decade ago and saved a few pennies in the process got a promotion. 

Again...if you see hydraulic fluid on the ground best not to drive the car, if a leaking brake line bursts especially with SBC brakes it can turn into a dangerous situation in a nano second. 

Bottom Line:

Replaced the left and right brake line and bled the brakes. Absolutely not lingering on what could have happened if the brakes failed.

 


 

Tuesday
Sep232014

The Wheel Alignment

We have replaced most of the front suspension components on Walter, be it suspension arms, ball joints, and more suspension arms.

When so many components are replaced, the thought turns towards perhaps the car needs a wheel alignment. It was all good for most of the compnents until the last suspension arms were replaced. At that point the steering was slightly off center.

One gets busy, the crank sensor decides to stall the car, the windshield crack decides to start travelling up the  windshield.

The summer tires are soft, and stricky, and especially the front have a tendency to wear on the outside edges (we know why up to a point).

A few weeks ago we notice that the left front tire has more pronounced wear on the outside edge than the right front. It creates a "oops moment", and who has time to go chasing after a wheel alignment.

The other thought is "This is never ending, every month something crops up". Then our innate sense that the car must be right takes over, and obvious we proceed to get a wheel alignment. 

As expected the toe in of the left front was off, and creating the more pronounced wear. 

What a surprise nothing is loose in the front suspension. No kidding...there is nothing left to be loose, its all been replaced.