Been reading the info on synthetic oils and have decided to use straight oil for the engine and regular lubricants as called for in trans and diff.
The question I have is with Silicone compared to Castrol GTLMA.
Moisture seems to get in the pistons of brakes and wheel cylinders making for an endless repair job. MG's, Sprite & Triumph.
For the Jag I have had all items replaced or rebuilt and new ss lines.
I would like a good clean driver without having to contend with hydralic problems and ruined paint from the brake fluid.
I had my front calipers rebuilt at Apple. Came with notice not recomending Silicone. Were they just covering the warantee or is it safe to use Silicone with a complete rebuild?
Thanks

Richard Sabonis
1965 E-Type Roadster
#10018

Submitted by bonnettoboot@e… on Mon, 05/29/2006 - 19:47

I find these discussions about Silicone fluid interesting, In my shop we have used it for 25 years, with original cylinders, and brass and stainless resleeves, We have done every thing from just bleeding out the system with silicon until it comes out at the nipples, to full conversions (everything new). How many I could't tell but in the last three months we have done 2 e types and a mark 9 and a 72 BMW 3.0 CSI. Furthermore,t6his has been on many makes from my 73 El Camino to a Rolls Royce silver shadow. WE HAVE NEVER HAD A PROBLEM. We do of course put a label on every car to indicate the fact. As for "eating" lines what does that mean? steel lines or rubber hoses? I have had contamination cases come in where the fluid was like jelly but never had a rotted hose or line! On Steves' tiger if it was restored the brakes should have been done also and it is easy to distinguish silicone from glycol. Have I been just lucky? Jaguar affectionado and etc.

Submitted by ianc@uvic.ca on Tue, 04/18/2006 - 14:25

Having stated categorically (in a previous thread) that I don't like silicone brake fluid, let me expand. The greatest benefit to silicone fluid is that it doesn't absorb water, so the boiling point stays high. As long as you don't allow water near the reservoir, your silicone filled system will be water free. Glycol fluids are hydroscopic, and will suck water out of the air, so there will always be some water in the system. BUT if you keep the lid on the reservoir except for brief periods, the amount of water absorbed by glycol fluid is tiny - might be 3 or 4% over a five year period, enough to lower the BP 5 C, not enough to worry about. In the past, if you were racing, and heat build-up was a concern, silicone HAD an advantage. Now, glycol-based DOT 5.1 (don't you wish they'd called it DOT 6?} maintains its boiling point even with water in it. So there is NO reason to go to silicone. And if you don't get every trace of glycol out of the system when you change over, the two fluids will form a jelly, which doesn't move through the system very easily. (Note that the entire system will not be full of this colloid: just the amount produced by the quantity of glycol that was present. If you leave 2 CC of glycol, you'll get about 4 CC of jelly. Still not a good thing.) Oh - silicone fluid is probably better for the environment. When you change fluids, the old glycol gets tossed somewhere, and it's very toxic stuff.

Ian Cameron
1969 E Type OTS

Submitted by dougi@shaw.ca on Mon, 04/17/2006 - 22:23

With a complete rebuild, it is safe to change the type of fluid. But I would suggest giving it a long hard look before using silicone. Moisture will get into the braking system no matter what kind of brake fluid you use. This is not debatable. The question is what happens to the moisture once it is in there. With glycol fluids like Castrol GTLMA (my choice) the moisture is absorbed by the fluid, and yes, while that lowers the boiling point, the benefit is that the moisture leaves the system when you change the brake fluid, which is a must-do no less often than every two years. With silicone fluid, the moisture is not absorbed, so it just finds its own little hiding places inside the system, and may or may not leave the system with a fluid change, and you need to change it no less often than every two years also. The only benefit of silicone fluid is that is won't eat your paint. We won't get into the softer pedal that silicone very often provides.....

Doug Ingram
Victoria BC Canada
1969 E-Type OTS
1987 XJ6 VDP
2002 X-Type