Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing DOT 5 Brake Fluid - Any Good?

Hello TMers

Just been watching a episode of 'Shed Racing' and Ivan and Suzie have been repairing/replacing the brakes on a 1960s Ferrari. One of the jobs i will be doing very soon is replacing the brake fluid in the MOG. But during the Winter i will strip down the front brakes for a good clean up. In the comments page of the video someone has stated that he uses a DOT 5 brake fluid. As it is a silicone based, it doesn't absorb water. Has anyone in TM world used this? About 5 years ago i read in Practical Classic magazine about this DOT 5 that they recommend using this (I think), alas i have lost the magazine!

Your thoughts and comments are greatly received.

Regards

Personally, I stick with Dot 4. No compatibility/contamination problems and as I change it every 2 or 3 years water absorption isn't an issue.

I'm quite happy to accept that Dot 5 may be better in extremis but I've never had any problem with Dot 4 and I'm a fairly enthusiastic driver.

I changed my brake fluid earlier this year, I bought a new 4 litre container of fluid and a tester to check whether the old fluid showed any sign of contamination. Not a sign, and I tried it on an already opened bottle of fluid (although the cap was on tight) left over from the last time I flushed the brake lines. No sign of any degradation.

Agree that DOT 4 is all you need. However, in my experience, it’s the rear brake cylinders that require the maintenance attention rather than the fronts. They are prone to seizing up if the pistons are not greased under the boots. Ctek grease is ideal.

Very true, I fitted new rear brake cylinders this year after one started weeping. The old ones had lasted 15 years or so, so I wasn't complaining.

DaveK, I recommend sticking to Dot4, bleeding the brakes every 2 to 3 years, and paying close attention to the rear cylinders, as they are prone to corrosion due to being factory-fitted with no packing grease. It's a job I had to do on my 2011 4/4.

I would stick to DOT4. You could be making a rod for your own back unless you replace or clean everythig thoroughly.
GoMog explains why here

Hamwich, Deejay, OZ 4/4 and John V6.

Many thanks for your replies. I will stick to DOT4, As i have used in the past. Understand your point about the rear cylinders. I replaced them about 6 years ago and do regularly check them.

Regards

The Dot 5.1 is an improved Dot 4 that can mix with Dot 4.

Harald

IWhen I rebuilt my car. replacing the whole brake brake system 30 years I went with Dot 5 silicon.
I
t has worked perfectly, I flushed the system with new about 5 years ago, I didn;t notice any difference/

As a car I now use mostly in the summer months, with copper brake pipes and stainless hoses, the brake system hasn;t caused me a single issue since I went over to Silicon fluid.

I can sense a fight here, between DOT 4 verses DOT 5 😃