Brake Fluid Flush Questions? - PeachParts Mercedes-Benz Forum

GradyService · #1 11-08-2007, 05:58 PM

If this has "never" been done to your 20+ year old MB, should you do it now?

Thanks, Dave.

MB-Dude · #2 11-08-2007, 06:01 PM

I think so. However, I'd wait until the very dry weather of late winter/early spring.
Cheers,
Jeff

Arthur Dalton · #3 11-08-2007, 06:07 PM

I would spray the bleeders with BP Blaster for a couple of days before attempting to break them loose.. old ones will snap right off if you don't take
that precaution..

GradyService · #4 11-08-2007, 06:08 PM

Okay, thanks for the prompt response. Now, should a MB be pressure bled, or done the old fashion way. Also, what brake fluid should be used? DOT4 or?

Thanks, Dave.

Arthur Dalton · #5 11-08-2007, 06:10 PM

Dot 3 or 4 is OK,.
No system should be bleed the Old Fashion way.

ScottinSoCal · #6 11-08-2007, 06:13 PM

Quote:

Originally Posted by GradyService

If this has "never" been done to your 20+ year old MB, should you do it now?

A qualified 'yes'.

It should definitely be done, but there are three ways to do it. I would only consider two of them.

There's a pressure bleeder that hooks up to your brake fluid container and pushes new brake fluid through the system. There's a vacuum bleeder that hooks up to the caliper bleed and pulls new brake fluid through the system. Then there's the old-fashioned method of having someone sit in the driver seat and pump the brake pedal to build up pressure while someone else bleeds the brakes.

The first two would be fine, but they'll take some extra equipment you may or may not have. The last one is almost guaranteed to damage the seals on your calipers after 20 years of sludge buildup. Forcing the piston and seal to go well beyond the normal range of travel with crap in the way is a recipe for damaged seals. If you don't have the equipment and don't want to buy it, take it in to someone who does have it and will use it. I got a pressure bleeder for less than $100 and it does a beautiful job. I also got a hand vacuum pump for less than $30 and it included a kit to vacuum bleed the brakes.

280EZRider · #7 11-09-2007, 12:32 AM

On any car that has not had a brake-system bleed for 20 years, I would not waste my time bleeding the system without first rebuilding or replacing the calipers, master cylinder and rubber lines. Once this is done, I would prefer the old fashion way of bleeding.

whunter · #8 11-09-2007, 02:03 AM

Quote:

Originally Posted by GradyService

If this has "never" been done to your 20+ year old MB, should you do it now?

Thanks, Dave.

Please look through this thread for answers to your questions.

ShopForum > Do It Yourself Links & Resources > DIY Links by Parts Category
Brake:
Brake:

Have a great day.

t walgamuth · #9 11-09-2007, 06:43 AM

I would not hesitate to do it without rebuilding calipers and such. No harm in trying. I always do it the old fashoned way. I have never had a problem with hyperextension of seals.

I once had a spill with a power bleeder and after wiping brake fluid off the ceiling of my garage, myself and my collector car, I lost all enthusiasm for the small amount of time saved by the use of them.

Tom W

cf · #10 11-09-2007, 01:19 PM

Quote:

Originally Posted by ScottinSoCal

The last one is almost guaranteed to damage the seals on your calipers after 20 years of sludge buildup. Forcing the piston and seal to go well beyond the normal range of travel with crap in the way is a recipe for damaged seals.

Old fashion precaution:

Check the brake pedal travel limit.
Get a piece of wood thick enough that would stop the pedal before it hits the lower limit when placed under the pedal.
Then when you manually bleed the piston rod would not over travel and hurt the seal.

Kestas · #11 11-10-2007, 12:06 PM

Has the car been sitting unused for a long while, or has the car been in continuous service for the past 20 years?

GradyService · #12 11-10-2007, 12:32 PM

In continuous service.