Why should I flush my brake fluid every year, you ask? - Page 2 - PeachParts Mercedes-Benz Forum

#16 05-31-2002, 02:15 PM

Quote:

Originally posted by MVK
do you folks think this will work for bleeding. It sounds good. any other suggestion on flushing/bleeding the brake system. I have to do that on my MB and my wife's Accord.

http://www.mityvac.com/techindex.html

MVK

This works better.

http://www.motiveproducts.com/ordernow_bleeders.htm

thebern · #17 06-01-2002, 05:23 PM

Could this be why car pulls to the right and breaking is minmal in the rain/wet?

240 Ed · #18 06-02-2002, 01:18 AM

It should not have anything to do with rain, and hydroscopic, etc.
Sounds like you have front calipers which need to be taken apart and cleaned, and perhaps new seals put in.

I would try bleeding/changing the brake fluid first. That can free up the caliper sometimes.

ATLD · #19 06-02-2002, 01:45 PM

I think you mean Hydrophylic not Hydroscopic (hydro=water; phylic=love), but I could be wrong.

ATLD

Arthur Dalton · #20 06-02-2002, 02:07 PM

Quote:

Originally posted by ATLD
I think you mean Hydrophylic not Hydroscopic (hydro=water; phylic=love), but I could be wrong.

ATLD

The correct term is :
Hygroscopic

#21 10-31-2002, 07:35 AM

I know it looks funny but, yacht!
from Middle Low German jacht, short for jachtschip, literally, hunting ship.

DieselHead · #22 10-31-2002, 09:07 AM

Has anyone ever used that Power Bleeder? I'm embarassed to admit that I haven't bled my brakes in........ years mostly because I'm too lazy to solicit the aid of someone else to pump the brake pedal. If that kit works well, $45 seems pretty reasonable and it would promote more frequent fluid changes. Thanks.

ALex

Stevo · #23 10-31-2002, 11:12 AM

We tried using my Mity vac to bleed the breaks on a 300sd and it didn't work so hot so if someone has done it that way please speak up as we didn't have much luck. We wound up doing it the old way. I have read some interesting info regarding bleeding the old way, and that is when the pedal is pushed beyond its normal travel you stand a good chance of damaging the master cylinder. The little "plunger" gets into a part of the cylinder that its not used to being "matted" with, Yata, yata, yata anyway thats the theory I heard.

Have also heard good stuff about that other system where you pressurize the master cylinder, one man (or woman) job.

#24 10-31-2002, 12:56 PM

I have never used the vacuum bleeder either, but I did pick up a clue that last time I set out to do the brake flush. Go spend a couple of bucks at the grocery store and get a turkey baster. Use that to empty the brake fluid resovoir and fill it with clean. Then start in on the flush. Speeds up the process.

Richard Eldridge · #25 10-31-2002, 01:23 PM

My old 1977 Toyota Celica once got a seized wheel cylinder. When I replaced it, I noticed that there was a rust spot, nearly round, on the inside of the cylinder, just as you would assume would be made by a drop of water trapped inside. In addition, the fluid was nearly black.

I assume that this stuff was black because it had slowly been dissolving rubber from the seals and other rubber parts, since dust would have a hard time finding its way into the master cylinder.

I had heard of silicone brake fluid and replaced the system with silicone fluid, using a Mity-Vac.

The car seemed to have a harder pedal, and stopped as well as any car with disc/drum brakes. I never had another wheel cylinder or caliper go bad after that, over 75,000 miles and 7 years.

I also replaced the fluid in my wife's 1980 Toyota Corona. Again, I never had another brake problem, other than usual wear.

Before that, the procedure was to replace both wheel cylinders and all the shoes everytime the damned thing seized, roughly every 3 years on every other car I owned. When I as younger and more foolish, I would take the brakes to Midas and they would change all sorts of stuff, but leave the fluid as dark as it was, unless changing the Master Cylinder. I assume that this was in hopes of zapping me again with their greatly overpriced, not necessarily needed and not all that competent work.

Then a neighbor showed me how to do brakes myself.

The silicone fluid did not change in color in 7 years on the Celica and 6 on the Corona.

On my Mercedes, I used DOT 5.1, being as they don't recommend silicone DOT 5.0.

The question is Being as silicone is so obviously better than hygroscopic fluid that has alcohol in it (which is why it attracts H20, why does MB not use silicone fluid? Is this related to the Automatic Brake Pumper gizmo?

Peter Fearing · #26 10-31-2002, 06:39 PM

I have a '78 Chevy that I bought new. To date it has 96K miles. I installed new front pads 20K miles ago. The owners manual does not indicate or suggest anywhere that you should ever change the brake fluid. I have never changed the brake fluid and the brakes work perfectly. What do the Chevy folks know that the MB people don't?

240 Ed · #27 11-02-2002, 03:24 AM

Peter;

There is a bit of irony here.
I first heard about changing brake fluid once a year from a woman Mercedes owner who had just had her car serviced at the dealer. I looked at her bill and there it was, "changed brake fluid" on the bill. I thought she had been ripped off, and was a bit pissed! on her behalf of course...
That started a line of inquiry about brake fluid and I learned quite a lot about it.

I agree with you that none of the older american cars or mechanics ever suggested changing brake fluid. Turns out they were wrong. what usually happens is that the master cylinder "goes out"-it's replaced and bled and everything is okay again. It goes out because of the water contamination! Properly maintained and flushed, you actually shouldn't ever have a problem with brakes.

Richard;

You live in a very humid climate and your fluid will get dark rather more quickly than someone in Arizona.

Silicone brake fluid. DOT 5
Standard equipment on Porsches I think.

I have heard of reports from people who have switched to silicone fluid that they experience a softer pedal, and prefer the DOT 5.1. I believe that this is standard equipment on Audi and Jaguar.
I think Jaguar and Lucas were leaders in this fluid and that Jaguar insisted on this fluid in their equipment saying that their seals were incompatible with DOT 3 and 4.

PLEASE DO NOT BUY DOT 3 !! just because it is cheaper...
DOT 4 or DOT 5.1 is compatible and should be used.

#28 11-02-2002, 10:21 AM

After reading the posts here, I am going to change my brake fluid today. I am going to use some DOT 4 fluid, and I am going to use my new vacuum pump/ brake bleeder, I am hoping that everything will work smoothly.

#29 11-02-2002, 11:24 PM

I had problems with my vacuum bleeder today, so I had to do it the old fashioned way, which I still think I didn't get all the air bubbles out because it still feels a little spongy.

dabenz · #30 11-03-2002, 12:25 PM

Peter, a few decades ago somebody said that there isn't an American solution to every issue. We have the most vehicles, but not all of them. Not bleeding brakes every year is like filling engine oil to the full line on the dipstick.

Here's some tips for vacuum brake bleeding: I use a glass turkey baster to suck out old fluid from reservoir and replace with new before starting. Then tie the brake pedal back (toward the seat). I built a dump jar from a peanut butter jar and three fittings. Two fittings are 3/8in male threaded on one end and barbed on the other. The third is 3/8in female and barbed. Doesn't matter if nylon or brass, buy at a farm or home supply store. Drill two holes in the jar lid, silicone and screw the male fittings into the top of the lid. Screw the female onto one of the males (you might need washers to take up the slack). A small piece of tubing on the inner barb (enough to reach the bottom of the jar), a 1 1/2ft piece between the outer barb and the brake nipple, a 1 1/2ft piece of tubing between the empty barb that is open at the inside of the lid and your hand vacuum pump. Screw the jar on the lid, place it in an old coffee can, loosen the nipple, and pump away (If nothing happens by the fourth or fifth pump then pull the tubing off the nipple and clean out the nipple with a piece of wire or replace it. You don't want the jar to implode and hurt somebody, and this won't happen if you bleed yearly and put a rubber boot over the nipple when done). You only need to make sure you don't empty the car reservoir (start over) and to empty the dump jar before the level reaches the lid (you may get brake fluid in your vacuum pump). The coffee can is dual purpose: helps keep the dump jar upright and provides a place to store the dump jar and tubing. Once you get the hang of it a good job should cost a quart of brake fluid and and hour of time including cleanup. Compare that to the cost of brake parts and time or an accident on the road. Ditto DOT 4 being the minimum spec on the fluid.