Brake fluid

Discussion of TABC-related matters
Post Reply
timandgerda
Posts: 97
Joined: Thu Oct 22, 2015 12:50 pm

Brake fluid

Post by timandgerda » Wed Aug 28, 2019 3:32 am

I have completely rebuilt the brake system on my TC and was planning to use silicon fluid but have read that it doesn't give a firm pedal. Is this true and any advice on alternatives would be welcome. Cheers. Tim.

User avatar
Marv
Posts: 240
Joined: Sat Oct 03, 2015 7:34 pm

Re: Brake fluid

Post by Marv » Wed Aug 28, 2019 10:08 am

I recently rebuilt the brake system on a MGB and a MGA and changed both over to Silicone DOT 5.0 Silicone. Don't mistakenly get DOT 5.1 which is just a refined version of DOT 4.0 Glycol Based Fluid. I did not experience any loss of brake pedal feel in the changeover. In fact the only scenario I've read about spongy pedal and DOT 5.0 is that DOT 5.0 should NEVER be mixed with glycol-based brake fluid. If you do, it is not unusual to expect spongy brakes, poor braking performance, and even damage to caliper seals and hydraulic seals.

Tom Lange, MGT Repair
Posts: 193
Joined: Mon Jan 07, 2013 10:14 am

Re: Brake fluid

Post by Tom Lange, MGT Repair » Wed Aug 28, 2019 11:56 am

Silicone brake fluid is another of those subjects on which you will get polar opinions. I have used it for years, and strongly recommend it IF the system is entirely rebuilt/replaced, and IF you flush the system with alcohol first.

Dot5 does not like air bubbles, so agitate as little as possible and push down and release the brake pedal gently when bleeding. A vacuum bleeder proves its worth here! Getting all the air out of a silicone fluid system is harder (which is why you hear that it results in a soft pedal), but once bled with no air in the system, the pedal is hard as a rock. Be prepared to need to bleed it three or four times the first time, to get all the air out, but the end product is worth it, IMHO

Tom Lange
MGT Repair

User avatar
Steve Simmons
Site Admin
Posts: 1008
Joined: Wed Dec 26, 2012 10:48 am
Location: Southern California
Contact:

Re: Brake fluid

Post by Steve Simmons » Wed Aug 28, 2019 3:16 pm

I fully agree with the above. While I don't use it in the TC, I do use it in several other cars including MGA, MGB and MGC. The only downsides I've found are a bit more difficulty bleeding, and cost / availability.
1949 TC8975 / XPAG 9609
1949 TC9849 EXU / XPAG 10507
http://www.mgnuts.com

User avatar
stephen stierman
Posts: 311
Joined: Mon Jan 07, 2013 6:12 pm
Location: worthington, ohio USA

Re: Brake fluid

Post by stephen stierman » Thu Aug 29, 2019 6:35 am

I use silicone in all my old cars and have for years. As long as you renew all the rubber parts and thoroughly clean out the old fluid it is just fine. I would use nothing else as my cars often are not used for several months during the winter and there are no problems.

User avatar
bloodysalmon
Posts: 123
Joined: Mon Jan 22, 2018 4:10 am
Location: Kirkby-in-Ashfield, Notts, UK

Re: Brake fluid

Post by bloodysalmon » Sun Sep 01, 2019 1:58 am

interestingly, how do people best 'bleed' the brakes, on your own ... how? Tools ... gizmo? :thumbs:
Chris Blood
TC1472,TC2686,TC4245,D-type D0407

timandgerda
Posts: 97
Joined: Thu Oct 22, 2015 12:50 pm

Re: Brake fluid

Post by timandgerda » Sun Sep 01, 2019 1:02 pm

Thanks all. I am going with Dot 5 and have an Eezibleed kit so will let you know how I get on (I haven't got the fluid yet so may be a while!)

User avatar
stephen stierman
Posts: 311
Joined: Mon Jan 07, 2013 6:12 pm
Location: worthington, ohio USA

Re: Brake fluid

Post by stephen stierman » Sun Sep 01, 2019 1:24 pm

My wife will pump the peddle, now if I could just get her to crawl under to access the rear bleeders...…..

Duncan M
Posts: 409
Joined: Fri Oct 10, 2014 9:08 pm
Location: Northern California

Re: Brake fluid

Post by Duncan M » Sun Sep 01, 2019 4:16 pm

The ability of typical (DOT 3/4/5.1) brake fluid to evenly absorb moisture is actually a desireable characteristic, as long as the fluid is flushed every few years.

Post Reply