Old Dot 4 Fluid

[Dancer]

I have a sealed bottle of DOT 4 Brake Fluid more than 20 years old, is it still OK to use? I have just bought an old Peugeot based Autosleeper and the fluid levels are low so I want to use this if possible.

 

[The Coops]

Its fine as long as its sealed its once opened that it becomes hydroscopic ( absorbing moisture) Just check on the reservoir that its suitable for the system

 

[Dancer]

Thanks, The manual says DOT 4 . It's a bit difficult to see the level, but when taking the cap off I there is liquid, but no depth on the flat section of the container immediately below the cap so I have assumed it needs topping up. I can't see a max/min indicator on the outside.

 

[Winger]

But if your brake pads are say half worn the level will have dropped anyway and in time when they are nearly done you should get a red warning light so in my mind it would be counter productive to top it up

 

[Spriddler]

It may well be O.K. but it doesn't sound urgent and it's not dear so why take any chance on your safety? Buy some fresh fluid.

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[Catpirate]

Chances are it is your Brake pads wearing unless you have a leak. Better to check pads first, fitting new pads will restore the level. Over filling can result in spiilage and damage to your paintwork. As above your fluid is probably ok as long as it has been sealed.

 

[Dancer]

Thanks for all the advice. I have had another look at the tank and the level is OK, and I see from the paperwork the front disks were replaced earlier this year so I should have no worries there.

 

[Landy Andy]

Thanks, The manual says DOT 4 . It's a bit difficult to see the level, but when taking the cap off I there is liquid, but no depth on the flat section of the container immediately below the cap so I have assumed it needs topping up. I can't see a max/min indicator on the outside.

Put a torch to the side of the reservoir to show the levels

 

[Richard n Ann]

When I did supermarket refrigeration, I used to put liquid line filter driers in the oven at 100°c to remove all moisture. Not old ones but ones that were put on problem systems new to remove moisture.

Should be the same with old brake fluid. Bake at 100°c for one hour and all liquid water will evaporate leaving the dry oil behind.

Reuse and save the environment

Tin hat ready

 

[Rivermount]

If the container is metal and not rusty, it may still be sealed but very old.
If the container is polyethene then it may have taken up some moisture! Polyethene is not completely moisture proof over long periods of time.
Might be safer to buy a new bottle and get all the advantages of a newer product.

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