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MG MGB Technical - silicone break fluid

Folks,
I just wanted to ask what is the latest on use of silicone fluids. I have used silicone for a few years now in the B but have never been satisfied with getting all the air bled out. A 'double pump' is required to get good feel and I don't think I can lock the fronts on a panic stop. So am thinking on gonig back to Girling LMA. Any other thoughts on the matter?
Thanks, Geoff
Geoff Kimler

Geoff,

No doubt this will stir things up once again. All I can say is, I've been using it for the past 5 years in my 73 BGT with no problems. Bleeding can be a bit of a hassle, but other than that I see no problems. I recently installed new front pads and a SS hose set and my brakes feel quite good. No double-pumping required. You might want to fully investigate the entie system before making the change.

Cheers,
Dennis
Dennis

I've been using silicone brake fluid in both my MGA and BGT since 1985. No problem bleeding brakes or clutch hydraulics. Good, hard pedal. Insides of wheel cylinders and calipers are very clean after several years. Can lock wheels on stopping if I try hard. Don't see why I'd want to?
Anyway, I'd not go back to DOT 3.
Cheers, Fraser
Fraser Cooper

Your pedal problems lie elsewhere. Been running sillycone for over ten years. On track and off.Try replacing all the rubber hoses with the braided stell ones. Makes a huge difference.

Pete
Pete

Just to throw this out there..
I work at an Alfa Romeo restoration shop. Most of the older Alfas use British hydraulic wheel cylinders and master cylinders. We've had several cars come in that had the brakes stick fully locked, while driving in some cases, because they were running silicone brake fluid and it caused the rubber seals to swell up. The fluid was blue in color, and I'm not sure what brand it was. Also most of these cars were front and rear drums, which might make some difference. Obviously people here use it without problems. I personally prefer to use good Ate fluid or LMA.
just my 2 cents
-Bill
Bill Mertz

I use silicone brake fluid in my roatster and the V8 without any problems since many years.

The problem with double pumping seems to be another fault. May be hoses and lines should be compared with those of another car without these fault.
Ralph


Ralph

Hi, only problem i every had with silicon brake fluid was the fronts hanging on after heavy braking. Turned out that the fluid did not lubricate the servo.Changed back to dot3 and never did it again.Jmaie
j.peirson

Thanks everyone for your comments. I have checked the system for leaks thinking air is getting in somewhere and I think I have the SS hoses on the car. I will have to check again, maybe I have a leaky wheel cylinder letting in air. Since the consensus is positive I will stay with the silicone.
On the locking the breaks issue, when that semi-truck pulls over in my lane about ready to take out my front wing I want to be able to hit the breaks hard! with one stab of the right foot.
Cheers
Geoff
Geoff Kimler

Geoff:
Yabut, locked wheels don't stop the car as quickly as slowly rotating one, and they don;t steer worth a hoot!
Cheers!, Fraser
Fraser Cooper

If you hit the brakes (sp!) suddenly and hard you are far more likely to lock them than if you apply them progessively, and as Fraser says a locked wheel has precious little braking (sliding over a layer of liquid rubber) and no steering.

Never used silicone, but I have always fouind that bleeding the brakes on both my cars is a two-stage process to get all the air out. Low pressure from a gunsons Eezi-Bleed or pedal to fill the system, then high pressure from someone standing on the pedal while I rapidly open and close the caliper bleed nipples in turn, which always gets an extra 'lump' of air out.
Paul Hunt 2

This thread was discussed between 09/06/2006 and 16/06/2006

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