Motul 660 vs Castrol SRF
 

FCP Euro is backordered on Castrol SRF...went with 660 in the meantime until SRF is back in stock...The first day I took out the 991.1 C2S, the OEM fluid got cooked. From what I am reading, the 660 takes on moisture more quickly and needs to be changed more frequently. Just wanted to get other members' experience.

I have no experience with either but you can get Castrol SRF for $68 shipped on Amazon.

Yes, it is available from other avenues...I prefer using FCP Euro as their parts replacements are free after the first purchase.

Castrol SRF hands down.

If you want the very best then go with Endless RF650.

It would be pretty generous of them to "replace" SRF... Maybe that's not what you meant, but if not, just use amazon.

All brake fluids absorb moisture. I can't say wether Motul 660 absorbs it any faster, but I can say that SRF has much less drop in the boiling points between wet and dry than the Motul, which is what makes it a great fluid for street/track cars. Even when "wet" (absorbed some % of moisture), it still has a sufficiently high boiling point to be usable on track days.

Buy it once and you won’t have to pay for the second round. Are you familiar with their lifetime replacement? I use it for brakes and oil changes. I stopped paying for replacement parts (after the first purchase) years ago.

yes, of course... just not sure what that has to do with buying brake fluid that they don't have in stock.

All I was asking was anyone’s experience with Motul 660 vs SRF since I will be using it until the SRF goes back into stock there. There is still a credit applied when the return for the new product is made.

wow... OK, best of luck.

Motul rbf 600 and 660 work well, but require relatively frequent changes. Castrol srf definitely lasts longer.

Do you rebottle the fluids and ship it back to them? Curious

Correct. Dump old fluids in the new empty bottles. I use USPS flat rate boxes to cut the cost on shipping back...great for all fluids (engine oil, trans, brake, diff), filters, wipers, and brakes.

I used Motul 660 for a couple of years and thought it was great until I started using the SRF. I found two differences that made a difference. First it lasts longer, second I found better modulation of the brakes. For me the cost is not a material factor as I found I used 2x as much 660 in one track season as opposed to the SRF.

Sounds good..will be switching to SRF...switch to FCP Euro and you will only have to pay for SRF one more time for as long as you track.

So you send back all your used motor oil as well?

Wow, IMHO that's just wrong. Kind of like the ladies I see returning dead Christmas poinsettias to Costco in March. But I'm glad you found a loophole that saves you a few bucks...