Morris Minor Owners Club

Thanks for that,it is very interesting.
I have used Silicone fluid for many years and would never go back. Every year I had to dismantle the rear cylinders to clean them of rust and grime. After doing a complete brake set up change using Silicone fluid have never had to sort them out again. At the time I replaced all pipes and flexables, rear and master cylinders and fitted Ford based disks to the front. I do not have a servo or remote reservoir.
I can not recommend Silicone brake fluid enough if someone is doing a complete overhaul.

Hi, just thought I would add to this post. I have use silicone on my vehicles with no problems. Went over to silicone on my 1954 Triumph over twenty years ago, Morris Traveller when I got her last year, I changed over immediately. Also ran on my 1200cc bike. So many good points, especially no damage to paint work, brake rubbers etc lubricated, never needs changing etc. The Morris is our every day car and the TR is used all year around. I have never had brake fade or any other issues. Cannot rate the stuff highly enough. The brand is as the post. All best Mike

Thanks les, an interesting read.
As I have posted elsewhere on the board, Automec DOT5 (Silicone) was used, in my car, after a complete brake system component renewal about 25 years ago. It is advertised as "for life", but as a precaution I did a fluid change about 6 years ago. There was no appreciable difference, to the removed fluid, from when it was new. A test indicated zero moisture content.
No problems with the system in that time - except, I had to renew a rear wheel cylinder because the handbrake lever on the cylinder failed rsulting in the shoes not fully releasing.

I use Automec Dot 5 too. Great stuff. For many years I had to replace seized cylinders, now that is a thing of the past. I have read ill-informed articles that say Silicone brake fluid is more difficult to bleed but I have never had an issue. Actually, I would argue it is easier to bleed because it won't strip paint! The only downside is that it is expensive BUT it does not need to be changed every 2 or 3 years and the money saved by not having to replace corroded seized cylinders actually makes using Silicone brake fluid much cheaper in the long run.

Stephen

How do you flush the system to be completely clear of DOT4 fluid? My understanding is that the two are not compatible.

ndevans wrote: ↑Thu Sep 04, 2025 7:47 am How do you flush the system to be completely clear of DOT4 fluid? My understanding is that the two are not compatible.

Read 1st line on the document Les posted

"articles that say Silicone brake fluid is more difficult to bleed but I have never had an issue."
Nor I Stephen. However, I have only needed to bleed thrice. 1st at the original brake system/component renewal. 2nd when the fluid was changed. 3rd when that wheel cylinder was changed.
Although I do use a Gunson Eezibleed with a master cylinder cap modified for the outlet pipe connection.

Mervin wrote: ↑Thu Sep 04, 2025 10:41 am "articles that say Silicone brake fluid is more difficult to bleed but I have never had an issue."
Nor I Stephen. However, I have only needed to bleed thrice. 1st at the original brake system/component renewal. 2nd when the fluid was changed. 3rd when that wheel cylinder was changed.
Although I do use a Gunson Eezibleed with a master cylinder cap modified for the outlet pipe connection.

I've had to bleed a few times. Original set up, when replacing flexible hoses, when upgrading to Wolseley 9" brakes. I've used both Gunson Eezibleed and standard two-man pedal up, pedal down and there was nothing to say about it really other than I had no concerns about spilling a bit of Dot 5 on the garage floor oh and I like the violet/purple colour of Automec Dot 5 . Seriously though, I would recommend affixing a warning sticker next to the master cylinder saying "Silicone DoT 5 ONLY!". You can buy such a sticker from "I Say Ding Dong": https://www.isaydingdong.co.uk/shop/sea ... q=silicone

Stephen

You see there is conflicting information out there. My previous understanding, backed up by some googling, has always been that silicon and glycol are not compatible, and that every last bit of glycol must be removed from the system before putting silicon in. This includes renewing all seals, as these become impregnated with glycol over time, and the water in them will separate out and pool because it can't be absorbed by the silicon.
I'm minded to try using DOT5.1, which is glycol compatible but owing similar performance to silicon.