Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Brake fade

Quite right! I do not know of a dealer that will change brake fluid unless requested, though a few of the good ones suggest it, especially if they have your service record.
A good rule of thumb is every three years unless you are in a humid climate, where it should be more often. There are cheap brake fluid testers one can use as well.

The only other watchpoint is to avoid silicone DOT 5 (unless you are a constant concours competitor).
However there are compatible brake fluids to what the Factory gave you that have a higher boiling point than. Dot 5.1 for example.

l.

A general recommendation is to change the brake fluid every 2 years, as brake fluid is hygroscopic.#

VW recommends the first change for new cars after 3 years and then every 2 years.
Why is the first change only recommended after 3 years? I do not know.

In any case, the water content in the brake fluid should be checked at appropriate intervals!
This is possible with simple testers and is done by every responsible workshop,

As the cost of a tester is more that 1 ltr of decent brand DOT 4, just change it ! All the doubt of 'is it the fluid' ? is gone and you reset your 2 year reminder from then...simples

Had a very similar pedal to the floor experience on a longish journey not long after I got this car. The rear brake cylinder was stuck and heated the fluid. There was very little drag noticeable just by pushing/rocking the car. Only really noticeable by spinning the wheel off the ground.

Jon, Are you suggesting he wait each time for his brakes to fail as they did before he changes the brake fluid? Brake problems are no fun.
The tester will save its cost many times over.

I imagine he is using DOT 4 like you are. It is the MMC favorite. However, DOT 5.1 is compatible and has a boiling point 40C (72F) higher than DOT 4
and 65C (117F) more than DOT 3. That is worth the extra couple of quid.

gmg

Stick to DOT 4, DOT 5 is really for racing only, has a higher boiling temperature but is far more hydroscopic but ok if you change regularly as you would on a race car.

I had a similar issue with my Plus4 of a similar vintage. I was never happy with the feel when I took ownership of the car, which was particularly bad when going down a hill with a T-junction at the bottom where the pedal went to the floor.

When I purchased the car it had been serviced every year by the same main dealership and had the benefit to check all the invoices and found the car had never had its brake fluid changed. I changed the fluid and checked the rear cylinders which had recently been replaced, however still not happy with the brakes.

In the end I decided to replace the brake master cylinder only to find the car transformed!!! I was grasping at straws as the car had only done 10,000 miles! But problem solved in my case.

Hope this helps, also, the master cylinder on my car was based on a Mini so cheap to buy. If you look on the body of the metal brake cylinder you will see the manufacturer’s part number.

It does make me wonder if some brake master cylinders on trads were left with machining swarf in the bores. Not many because it wasn't a "thing" on new trads, but makes me wonder.

It also makes me wonder if a high underbonnet temperature might expand the master cylinder just enough to weaken the seals.

A friend had a new FIAT back in the day. When it got hot, the brakes locked on. I don't recall why but it was a known fault with that model at the time, and the only way he could release them was to open a couple of bleed valves to get rid of the pressure. He did that at the side of the road, until something was fixed........

Thanks for the advice guys. I bought a fluid tester which came back as OK, but looking back through the service records I can not see any mention of a fluid change. I have tested rear brakes which are also fine. As car is SORN now until spring, I will take it for a fluid change once its back on the road.

Thanks for the help.

Actually, DOT 5.1 has a higher boiling point that silicone DOT 5 and is fully compatible with DOT 3&4.