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

[sapper740]

Originally Posted by BCBlitz

HI All

Well Im currious if any of you can chime in on the fluids issue for my F15A flathead V8 I dont have the manual yet so currious as to what to use in all the areas on the truck.

Here's a scan from my Ford manual for "Special Pattern vehicles" showing all the service lubricants, both DND specification number and civilian equivalent. If you want to send me your email address, I can send you a much higher resolution pic. Hope this info helps, Derek.

[Bob Carriere]

HI Terry

If you are looking for reproductions of the various Ford manuals contact Grant Bowker on MLU he now has the full collection of manuals from Alex Blair.

Sounds like you will be getting down and dirty soon.....

BooBee

[Gunner]

Hi Terry:

I have silicone in the brake system of both my 43 F60S Light Anti Aircraft Tractor (LAAT) and my 41 GMC CCKW and am very happy with them. Unlike several other trucks in the collection they never need bleeding. Many other of our beasts need bleeding every few months and one is a downright fluid hog who needs a bleed every month. When it is rebuilt shortly, its getting silicone!

There are, however, many traps and pitfalls in switching over. I strongly recommend you do a search on this and other forums to get an idea of whats involved... basically you will be replacing most of the rubber parts of the system before you add the silicone.

Rob Love, who posts here frequently, is a very talented ex-military mechanic and enthusiast. He has vast experience with silicone brake fluid and can set you in the right direction.

Good luck! Mike

[cantankrs]

I'm interested in where this silicone info is going - perhaps it should have its own thread in the restoration forum? A couple of years ago I enquired with a local, very experienced brake man, about whether I should bite the bullet and switch a light crane I have over to silicone brake fluid while I was overhauling the brake system and he flat out said don't touch the stuff. He wouldn't elaborate and seemed to have no love for it. I don't think he was trying to con me in any way. I just don't know whether he was warning me off due to cost, or some other reasons. Prior to that everything I'd heard said it was the go for restored vehicles.

Regards

Alex

[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.

[Neil Ashley]

I have been in the REME TA for 17 years and one of the most common jobs I do when working in workshops is replacing the Master Cylinders on trailers which have seized up due to lack of use. This is despite changing the brake fluid on a regular basis.

Silicone Brakle Fluid in an application like this could save thousands of pounds a year.

[Bob Carriere]

Just to echo Phil's point........

Last weekend, just a spur of the moment thing...... we decided to see if I still had brake pressure on my C15a which slept in a canvas tent all Winter.

Now my experience with M 37, M43 and PW was that the pedal would drop to the floor and a total bleed job would be needed...... that happens every year on my Dodges...... low and behold.... after two pumps, by hand, we had full pressure.
Sat on the beast and puched hard to see if it would bleed down.... held real thight......

So we pushed our luck a little further and tested to see if the battery still had life..... shit the engine started no problems at all......

Now when I rebuilt my C15a I installed new wheel cylinders, new steel and rubber lines and a rebuilt SS sleeved master, done by John Stuart of Stoney Creek, Ont. I hesitated like most to convert to silicone..... read all the pros and cons of the new fluid...got totally confused with the controversy...... some early experience were very negative..... it is important to note that most high end Ford cars (Lincoln and Jags)and trucks have switched to the modern silicone fluid......

For good dependable brakes do not hesitate to get new linings and get the drums turned clean..... and while at it..get them to "arc" grind your new linings to sit properly in the arc of the drums.....

If I had a chance to redo the full system of a Dodge, I would switch to synthetic silicone fluids. There are limits as to the improvement of the sick design of the flexible flower pot brake drums of the M37 as the stretch oval when braking hard..... it is a design limitation.

I would not consider using old, seemingly good, brake lines and would not try to flush them clean but rebuild the whole brake setup...... expensive.. Yes..... but so stopping a CMP on the rear end of a Honda.

Phil's expereince with the CMP is based on driving his trucks in the hills of Vermont and New Hamshire at a comfortable 50 mph... so when he says he can stop... he is not talking parade speed....!!!!

BooBee