Guys, I am looking to replace the proportioning valve and add self-adjusters to the rear my 55 Bel-Air ( I have power brakes ...disc up front...stock drums in rear... brake booster/mast cyl is off 79 Camaro ... Brake kit from SuperBell ) . If I want to switch from regular brake fluid to synthetic, what are the procedures? ... Should I also get a new Mast cyl / wheel cyls / calipers and then blow the line out with compressed air ? Do I need to run all new lines ( in which case, I'll just flush what I have ) Where do I begin ?
As always, any help and advise would be greatly appreciated ... Thanks in advance ... sdtsdt

Synthetic brake fluid should be compatable with your standard fluid. I have used the Motul synthetic in my race car and saw no problems with it, I did no special flushing other than a good bleeding every time I race.

I would remove the fluid in the reservoir, refill with Synthetic and bleed a little extra to get all the old fluid out.
David

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Check my web page for First Gen Camaro suspension info:
David's Motorsports page (http://ourworld.compuserve.com/homepages/David_Pozzi/)
First Gen Suspension Page (http://ourworld.compuserve.com/homepages/David_Pozzi/first_gen_suspension.htm)
67 RS 327 original owner. 69 Camaro Vintage Racer, 65 Lola T-70 Chev SB Can-Am Vintage Racer

I thought I read somewhere that the DOT 5 is not compatible with any other fluids ? ?

I may be mistaken, but I think DOT 5 is silicon based and is not the same as synthetic fluid.

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Bret Copsey
'68 Camaro base coupe
'92 Caprice wagon
'98 Malibu

The valvoline website say that DOT 5 is silicone-base and IS NOT compatible with regular brake fluid ... The website also says that silicone base may give mushier brake feel than conventional and that solicone-base will not eat paint. I like the not eat paint part ... However, if changing over means a complete rebuildof the brake system, I'll probably just flush with a DOT 4 fluid. Any comments???

Check out this link to Motul products mentioned by davidpozzi. Synthetic is not DOT 5 Silicone based-the terms are not interchangable, it's two different things.

As far as silicone DOT 5 goes, there have been plenty of posts here that pretty much say it's for cars that hardly get driven.
http://www.rallydist.com/motul.htm

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Bret Copsey
'68 Camaro base coupe
'92 Caprice wagon
'98 Malibu

Synthetic = Good
Silicone = Bad
Silicone fluid will make a thick gunk in the system, all old fluid should be flushed at the very least.
I know of no problems with synthetic fluids.
Just my opinion.
David

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Check my web page for First Gen Camaro suspension info:
David's Motorsports page (http://ourworld.compuserve.com/homepages/David_Pozzi/)
First Gen Suspension Page (http://ourworld.compuserve.com/homepages/David_Pozzi/first_gen_suspension.htm)
67 RS 327 original owner. 69 Camaro Vintage Racer, 65 Lola T-70 Chev SB Can-Am Vintage Racer

[This message has been edited by davidpozzi (edited 03-27-2002).]

Valvoline makes a good DOT 4 synthetic.

But when you think about it, aren't all brake fluids synthetic?

First of all, let me say ... Isn't it weird what they did with the DOT 5.1 designation ? ... Anyway, thanks for the input... I will go with a conventional fluid and keep it simple ... It has worked this long ... My main interest in the other was the paint issue, but I guess I'll just be careful as before ... ANyway, thanks again ...

I am dumber that a rock on this. How do you flush the old out is there something that you flush it with or do you flush it with the new stuff and how do you tell when you have all the old out. Thanks a lot

TIM

As a stock car chassis builder once told me, "don't waste money on DOT-5, it becomes DOT-4 as soon as you open the cap and absorbs some moisture."

I agree, the valvolene (sorry about the spelling) synthetic dot-4 works well... silicone stinks, no pedal feedback- not a bad choice for museum cars, it doesn't absorb water.

As far as flushing, I usually empty the master cylinder to within 1/8" of the bottom (don't un-cover the holes in the bottom), then refill with fresh and vacuum bleed starting at the right rear until the fluid runs clear, then do lr, rf, lf. (work from the farthest caliper back toward the master cylinder)

DOT5 silicone fluid is NOT compatible (chemically miscible) with glycol-based DOT3 and DOT4 brake fluid. If you really feel the need to convert, you need to completely flush the entire system with denatured alcohol to get the old glycol-based fluid out, and it's preferable to disassemble calipers and wheel cylinders and clean them with alcohol, and reassemble using DOT5 fluid as an assembly aid. When you refill and bleed, do it SLOWLY, as DOT5 fluid entrains air like crazy in microscopic bubbles, especially when it's agitated, which are almost impossible to get rid of (thus the cautions about soft pedal).

Big hassle for a street-driven car; you're better off using good old glycol-based DOT4 fluid (like Castrol LMA or Ford Heavy Duty) and bleed it once every two years.

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JohnZ
CRG
'69 Z28 Fathom Green

Thanks guys. Now lets see how big of a mess I can make of this.

TIM

Tim, I am going with the DOT 4 ... Anything else is more of a project than I want to see...