CMP fluids question ..........

[Phil Waterman]

Alex- your point is well taken, this topic does deserve detail treatment and it has been discussed in the past below are some of the threads. Unfortunately the MLU search feature works fine and other times it gets finicky. Today for example I typed in silicone brake fluid and got a number of responses, and then I typed in just silicone and got more. Yesterday I tried the same searches and got nothing. So if you get no hits on a search try again later.

Now back to silicone brake fluid here are some of the threads:
http://www.mapleleafup.org/forums/sh...ne+brake+fluid
http://www.mapleleafup.org/forums/sh...ne+brake+fluid
http://www.mapleleafup.org/forums/sh...ne+brake+fluid
http://www.mapleleafup.org/forums/sh...ne+brake+fluid

Several good points have been made in the past:

The first silicone brake fluids that came out had real problems and many providers/manufactures of master cylinders, brake cylinders, sleeving would not warranty there products if silicone was used.

If you are completely redoing a brake system (replacing or rebuilding all the parts) going over to modern silicone brake fluid should not be a problem and probably will give the advantages of silicone. But DO NOT use any NOS rubber parts, lines, cups or boots there maybe a compatibility problem. Be sure to use all new stock rubber parts from a known major brand. (This is probably a good idea know matter what fluid you use.)

The last point that has been made in the past discussions is that to change over, you really need to be sure that you get all of the old fluid and more importantly the dirt out of the system.

Personally - I think that one of the major maintenance problems with CMP brakes is us the users. We have all been spoiled by self adjusting brakes. Because the shoes/pads automatically adjust on our modern trucks and cars they have bigger brake fluid reservoirs because they are checked so infrequently. CMPs with there manual adjusting brakes need to be adjusted by the book. When properly adjusted the master cylinder is only moving a small amount to apply the brakes, which means there is very little air being drawn in and out through the vent on the filler cap thus less moisture is drawn into the system. When properly adjusted the brake shoes on a CMP do not have to move very much to fully apply. (This assumes that the drums are not oval shaped and shoes are not worn out)

Over the years I have been impressed with the braking power on HUP and on the C60, the HUP had has no booster while my C60S and C60L both have brake boosters. Compared to some of the US military trucks I've driven CMPs have bloody great brakes. (This however could be a maintenance issue) But when you look at the brakes on a 3/4 Dodge and compare it to a HUP you sort of wonder what was Dodge thinking.

One finial point – Alex I’m willing to bet that your friendly brake experts feelings about silicon brake fluid was centered around the rubber parts compatibility issue and the differences in tolerances between modern systems designed for silicon and those systems designed for regular DOT 3. Which is a very good point to consider.