Brake/Clutch Fluid

[Lin]

So, I have this nice new dual master cylinder “Sebring-type” pedal box for the Bugeye. I know this is the 3000 Forum, but the same issue applies to both models. I have all new brake cylinders for the rear drums, and new calipers for the discs in the front, and I will have all new brake pipes and hoses installed. I am going to go with silicone fluid this time. My question is: Do I need to disassemble the masters and clean with alcohol and then silicone? I really don’t want too, but I am assuming (very possibly wrong) that the cylinder seals were installed with a little regular brake fluid and I don’t want a problem as a result of mixing the two fluids. Is there really enough there to cause an issue? What do you think?

Lin

 

[John Turney]

My guess is that a tiny bit of conventional brake fluid was used in assembly, but when I installed my new MC's I didn't disassemble and flush, so I don't think it's required.

 

[BobHaskell]

The last couple of master cylinders I bought from Moss for our big Healey stated that the warranty was void if silicone fluid was used. Assume that yours doesn't have that warning.

 

[John Turney]

David Nock of BCS said that Girling voided the warranty is silicone fluid is used. My reply was that the warranty expired on my car 65 years ago.

 

[Bob_Spidell]

The last couple of master cylinders I bought from Moss for our big Healey stated that the warranty was void if silicone fluid was used. Assume that yours doesn't have that warning.

I 'voided the warranty' on the last M/C I put in my BJ8 about 10 years and 50K miles ago; I think this is a old wive's tale that won't die. OTOH I've seen DoT4 turn to gel in my BN2 that had to sit for a couple years.

 

[Lin]

Thanks, guys. I think I am going ahead with my plan to use silicone and I am not going to disassemble the masters. May be a while before I get it all done. Lots of projects.

 

[PAUL161]

10 years on a silicone system in my TF and it hasn't caused any problems yet! Just make sure the system is clean of all the old fluid, they do not mix! My entire system was new when I went to silicone, including the lines. PJ

 

[HealeyPassion]

I'm about to install a complete new brake system on my Healey project, BJ7, and plan to use silicone fluid. I think I'll call my dual master cylinder provider, Wilwood, and see what they say. I'll report back.

 

[vette]

I’ve had silicone in my BJ7 for about the last 18 years. No problems. No leaks. It was all new system when I put the silicone in there. I don’t think a wee bit of conventional in the masters would hurt. You could easily wash thru some wax and grease remover then immediately was in some silicone fluid.

 

[kodpkd]

Why do you want to use silicone? It doesn't hurt paint,,,,,, BUT, it's more compressible, the last thing you need in this brake system.

 

[Potts]

Why do you want to use silicone? It doesn't hurt paint,,,,,, BUT, it's more compressible, the last thing you need in this brake system.

I have had Dot 5 in the TR6 since mid nineties and just did the original calipers this past year though they had never leaked the dust boots were done. Longevity is what manufacturers are concerned with. Compressibility isn’t driver noticeable unless it is power bled. It does foam readily and easily results in small pockets in the system. Suction bleeding has always given great results but expect to need do a final crack of the bleeders after the first drive.
Cheers

 

[John Turney]

I've never noticed any compressibility with DOT 5. I have taken apart too many brake systems that used DOT 3/4 that were corroded, gunked up and unusable With DOT 5, when I take it apart it looks like new.