Changing brake fluid

dogboy73

I'm not exactly sure what type of brake fluid I have in my Avid Juicy 3 brakes. They can be used with Dot 4 or 5.1 fluid. I understand you can't mix the two how do I flush the existing fluid completely out & then add new 5.1 fluid? Do I just use a bleed kit & flush everything through a few times? Or do I need a seperate bleed kit for each type of fluid?

ratty2k

they can be mixed.

diy

Just flush it bottom up through as per the bleeding process then do a second bleed.

Personally I prefer 5.1 as it seems thinner and is easier to de-gas. Obviously don't buy cycle brake fluid when you can get car/motorcycle fluid for 25% of the price. Its the same stuff in a different bottle.

When selecting 5.1 which is very similar to 4, make sure you don't buy 5 by mistake which is completely different and wont mix

ratty2k

Only problem with buying car fluid (it is the same stuff) is volume. You end up with 1/2ltr stuck on a shelf for the thimble full you need in the bikes system.
De-gassing is IMO a complete farce. You dont de-gas a cars brakes...
5.1 is better, with a higher boiling point. But in a bike situation, barely relevant for most people.

dogboy73

Cool. Cheers for the replies.

Found this cheap bleed kit on e-bay. No fluid but the kit looks the same as the official Avid one;
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... K:MEWAX:IT

nicklouse

except the Avid kit comes with more tools and spare parts.

dogboy73

nicklouse wrote:

except the Avid kit comes with more tools and spare parts.

........ and costs more than twice the price!

dogboy73

......... actually the proper Avid kit comes with a nice bottle of Dot 5.1. Finish Line 5.1 costs over a tenner anyway. Suddenly that cheaper kit on fee-bay doesn't look like such a good deal :oops:

diy

I have the avid kit - paid 25 quid for it, from the pic in your link, I would say the non SRAM kit looks just as good. The only thing to check is that the syringe seals can take some pressure.

Personally I get much better results from degassing the fluid first. Car and motorcycle brake systems don't work the same way as Juicy's. I don't find the gas in the system comes out naturally. Its largely because the components are so small. But also because the design is a bit pants from a maintenance point of view.

You'll need about 200ml of fluid to flush both brakes and then about 100ml to do the final bleed.

CRC do 1/2 a litre of rock oil 5.1 for 8 quid.