Brake fluid replacement

[Lube Man]

I can find nothing in either the Owners Manual or the Factory Service Manual that indicates when if ever the brake fluid needs to be changed. There is some discussion of brake line bleeding which appears to involve a pressurization technique. Can anyone point to some info on this subject?



Before I bought my 99 Dodge I had a 1972 Chevy Van which I bought used in 1974. I never changed the brake oil and never had a problem with the brakes nor did I ever have a leak.



My 1980 Mercedes diesel manual says to change fluid once a year. I have owned that vehicle since 1990 and put 140,000 miles on it (odometer now read 249,000). Never changed the brake fluid on that one either.

 

[Cooker]

Brake fluid should be flushed regularly.



Brake fluid is hydroscopic, which means it absorbs water. When water is in the brake fluid the boiling point is lowered. On a panic stop where the fluid will get very hot, or while towing down the mountain, another instance where the fluid will get very hot, the fluid will boil at a lower temp causing your brakes to fade sooner than if you had fresh brake fluid. From this point of view, flushing your brake fluid regularly is a safety issue.



There are other negatives to having water in the fluid, many of them having to do with brake component life.



I think it should be done every two years, especially if you tow often, or at the very minimum every 100k miles.



I believe there was a write up some time back about this topic in a TDR issue. If I remember correctly Sam Memmolo wrote it.



-Ryan

 

[Lube Man]

Thanks for comments. I will replace the fluid but now need some instructions. There must be a simpler way than described in the Tech Manual. I have done a search of TDR and not come up with much.

 

[Cooker]

I know Sam Memollo did a write up about it (the flushing process) in an old issue. I see you have been a member for a while. I want to say issue 29,30, or 31.



The brake fluid to is also another important issue. Valvloine make a synthetic (or maybe it's semi synthetic). I have also read, and there is another thread going right now with this info, that the Motul 600c is an excellent fluid.



Let me know if you can't find the article.



-Ryan

 

[C Schomer]

I soldered fittings to an empty refrigerant tank and use 1/4" ID poly tubing between the tank and bleeder valve. I put the vacuum pump on the tank and open the bleeder valve. I can see thru the tubing when the clean fluid gets there. It's a one man job that way and takes about 15 minutes. I use about one quart of fluid each time. Craig

 

[Lube Man]

I don't know! I am convinced I should change the fluid but after reading the service manual it looks pretty complicated. Not just a matter of stepping on the pedal and opening a bleeder valve. Because of the ABS system it appears that there are several other bleeder points plus the need to use some type of vacuum and/or pressure system. Anybody care to comment on this. Is this a job for the weekend mechanic?

 

[Ram_Kowboy]

I am sure my method is not written in any service manual but its worked for me for years.



Open the reservior cap. Open the furthest bleeder screw from the master cylinder ( RR ). The brake fluid will begin to gravity bleed. DO NOT let the master cylinder run dry. Continuely add brake fluid to the master cylinder, soon you will see clear fluid draining from the bleeder screw. Close it. Go to the LR bleeder screw. Open it. Allow fluid to drain until it is clear. DO NOT let the master cylinder to run dry. Close the left rear and go to the RF bleeder screw. Then the LF. When all four bleeder screws have new fresh brake fluid running from them your system has been serviced. Top off the master cylinder and your done!



Did I mention... ... . DO NOT let the master cylinder run dry.



Good Luck

 

[Lube Man]

Your procedure makes sense. I have done this before with standard braking systems. But I have an ABS system and apparently there are additional bleeder points and more complexity associated with the ABS. Have you used your system with 4 wheel ABS brakes?



I spoke with a wheel and brake shop today and they charge $52 to flush and replace the fluid which sounds reasonable. They claim to have a special machine that can power flush the system which is alluded to in the DC tech manual. On Monday I am going to call my local DC dealer and see what they charge.