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Brake Fluid

carguy

Freshman Member
Offline
I am rebuilding the entire brake system in a BJ8 that I just bought. This includes rebuilding the servor, resivoir and cylinders as well as repaling the lines. The rubber parts in the resivoir are mush and many others are swollen. Someone in the past has used the wrong brake fluid. Since I am replacing everything can I use one of the newer brake fluids?
 
Hi Guy,
welcome to "The Great Forums"
For some reason brake fluid seems to be one of the more controversial topics. There are more opinions than there are brake fluids.

Some suggest a non silicone fluid such as DOT 4 Castrol LMA, others swear by a DOT 5 silicone fluid. I personally prefer a DOT 4 fluid.

I'll let someone else go into the details.
D
 
It seems that some affect the rubber bits and some don't. What products should we avoid? I have been using Valvoline Synpower with no apparent ill affects.

Thanks,
Walter
 
Well Walter, like Dave I prefer DOT 4 fluid I have no complaints regarding the brakes.However, If the fluid you are presently using has not created any adverse problems for you I would think it is ok in you application and safe to continue to use.--Fwiw---Keoke
 
[ QUOTE ]
It seems that some affect the rubber bits and some don't. What products should we avoid?
Thanks,
Walter

[/ QUOTE ]
Hi Walter,
I think that long ago Girling was using natural rubber in their brake parts. Some fluids caused the rubber to deteriorate. Girling recommended use of particular Castrol fluids to be safe. I think any brake parts that you get now will be a synthetic rubber which is compatible with almost all brake fluids. New old stock parts excepted. In any event, I don't know of any DOT 3 or DOT 4 fluids that will harm current rubber.

DOT 5, silicone fluid, will also not harm modern rubber, but has a few technical characteristics which some folks object to, while others believe it is an advantage.

As a matter of interest, any petroleum based products, even cleaning solvents, will harm natural rubber. Carguys original problem was likely caused by some sort of petroleum contamination, either accidently or by using some substitute fluid.
D
 
Thanks guys........you're awesome!

Walter
 
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