Which brake fluid type?
Discussion
Hi guys
Been doing a bit of an overhaul whilst it's cold and the last job is discs/ pads all round.
Whilst in halfords I bought some dot4 brake fluid to do a change with. Just by chance I had a look at the fluid reservoir lid today and it says, use dot3 fluid.
So, since I'm changing it, can I used dot4, or do I need to go out and get me some dot3?
Cheers
Been doing a bit of an overhaul whilst it's cold and the last job is discs/ pads all round.
Whilst in halfords I bought some dot4 brake fluid to do a change with. Just by chance I had a look at the fluid reservoir lid today and it says, use dot3 fluid.
So, since I'm changing it, can I used dot4, or do I need to go out and get me some dot3?
Cheers
Munter said:
MX-5 Lazza said:
Dot4 is fine. Dot5 is also fine but doesn't last as long. Don't use Dot4.1 or Dot5.1.
Lazza I think you have your DOT5 and 5.1 confused. DOT3, 4 and 5.1 are all compatible. DOT5 is silicone based and is not supposed to be used in systems designed for DOT3,4 or 5.1
You're right.Ok cool. and in terms of the changing procedure, do I need to pump ALL the fluid out of the system before I top up new, or can I drop it off one caliper and just top up the reservoir, mixing DOT3 and DOT4, to keep fluid in it and avoid getting any air in?
I have a pipe and one way valve to attach to the bleed nipple
I have a pipe and one way valve to attach to the bleed nipple
Do not "purge" the system before you start. You'll never get all the air out again! Start with the caliper furthest away from the reservoir with the longest run of brake pipe, and bleed that. Then next furthest away, next furthest and finish with the caliper with the shortest run of pipe. So, on my non-ABS mk1 I go nearside rear, offside rear, nearside front, offside front. Keep topping up the brake fluid reservoir as you go, do not let the fluid go below the min. line or you will get air in the system which you want to avoid.
The basic process is crack open the bleed nipple, brake pedal down to floor, close nipple, brake pedal up, repeat. Do three or four pumps, check the reservoir level and top up. This is much easier with two people, one on the bleed nipple and one on the brake pedal/keeping an eye on the fluid level and topping up. I've never had much luck with a simple "one man" bleed kit with one way valve but your mileage may vary. I use a glass jar and ensure the end of the bleed tube is submerged in a bit of brake fluid at all times, so you can't accidentally suck air back in that way.
You should be able to see the colour change in the fluid coming out of the caliper when new clean brake fluid is coming through, so you know you have done enough. Obviously it takes longer and more top-ups to push the fresh fluid through to the nearside rear where (on my mk1) there is a long run of pipe down the length of the car and across the rear subframe than it does for the offside front where there is only about a foot of pipe. Make sure your spanner is the right size for the bleed nipple as they are often like cheese and easy to round off. On mine they are different sizes front and rear, IIRC. Don't spill any brake fluid on your paintwork either, it is nasty stuff. It's a simple job if you do it methodically though.
If you've got a mk1 and are changing the disks and pads make sure you understand the rear caliper/pad/handbrake adjustment mechanism before you start too.
The basic process is crack open the bleed nipple, brake pedal down to floor, close nipple, brake pedal up, repeat. Do three or four pumps, check the reservoir level and top up. This is much easier with two people, one on the bleed nipple and one on the brake pedal/keeping an eye on the fluid level and topping up. I've never had much luck with a simple "one man" bleed kit with one way valve but your mileage may vary. I use a glass jar and ensure the end of the bleed tube is submerged in a bit of brake fluid at all times, so you can't accidentally suck air back in that way.
You should be able to see the colour change in the fluid coming out of the caliper when new clean brake fluid is coming through, so you know you have done enough. Obviously it takes longer and more top-ups to push the fresh fluid through to the nearside rear where (on my mk1) there is a long run of pipe down the length of the car and across the rear subframe than it does for the offside front where there is only about a foot of pipe. Make sure your spanner is the right size for the bleed nipple as they are often like cheese and easy to round off. On mine they are different sizes front and rear, IIRC. Don't spill any brake fluid on your paintwork either, it is nasty stuff. It's a simple job if you do it methodically though.
If you've got a mk1 and are changing the disks and pads make sure you understand the rear caliper/pad/handbrake adjustment mechanism before you start too.
Edited by cwinterb on Friday 28th February 16:30
it's easier with 2 people so that one can pump whilst the other checks the master cylinder isn't too low, and can see bubbles coming out the caliper and fresh fluid etc but it's not too painful as a one person job if you take a bit of care.
i don't bother with any bleeding kit, just a length of clear silicon hose into a jar. as long as the hose rises before it goes into the jar, you won't be drawing in any air as the bubbles will move away from teh caliper.
a litre is plenty to fully flush the brake system. take the opportunity to adjust up your rear calipers at the same time.
as above tho, DOT4 is fine. it's fully compatible with DOT3 but just a higher spec.
i don't bother with any bleeding kit, just a length of clear silicon hose into a jar. as long as the hose rises before it goes into the jar, you won't be drawing in any air as the bubbles will move away from teh caliper.
a litre is plenty to fully flush the brake system. take the opportunity to adjust up your rear calipers at the same time.
as above tho, DOT4 is fine. it's fully compatible with DOT3 but just a higher spec.
Edited by skinny on Friday 28th February 17:37
Gassing Station | Mazda MX5/Roadster/Miata | Top of Page | What's New | My Stuff