Going to change the brake fluid this weekend but I need to know how much fluid to actually buy, does anyone know roughly how much is needed?
Brake Fluid
- Thread starter mikerd4
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1 litre should do you, but I'd get 2 just in case. You can return the second if you don't use it.
2l.... however make sure you have vagcom available and know the sequence for bleeding the ABS system, I changed my fluid and needed to run this process to get a good pedal, and I was using a pressure bleeder to change my fluid
Dave B
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claudefrog said:
Any info on how to do this online I have access to vag com and will be changing my fluid over christmas?
Dave:icon_thumright:
I changed my fluid, you won't need VAG-COM unless you drain the system, a simple fluid change will not require it, all it does is cycle the ABS pump to purge the air.
Use a pressure or vacuum bleeder and start at the caliper furthest away from the master cylinder (n/s/r) and go slowly but surely.
Use a pressure or vacuum bleeder and start at the caliper furthest away from the master cylinder (n/s/r) and go slowly but surely.
Ess_Three
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If the system is currently full of fluid, you can simply flush through without a pressure bleeder. I managed just fine with mine. just use two people - one pumping the pedal and the other on the spanner at the bleed nipple.
Do the MS first...
Then calliper furthest from the MS, working back.
If it's full, 1 ltr will do you...20 pumps all the way to the floor, through each calliper should be enough, but you'll see the colour change of fresh fluid.
No harm in getting 2 lts though and doing the sequence twice.
Dot 4 will be fine.
But Dot 5.1 is an upgrade with a higher boiling point...but I seem to remember is is more hygroscopic so will need changing more often than Dot 4 can be left for (should still be fine for every 2 years though)
I'd use Dot 5.1 as it's compatible with the current Dot 4.
Don't use Dot 5.0 though...it's not compatible with Dot 4.
Do the MS first...
Then calliper furthest from the MS, working back.
If it's full, 1 ltr will do you...20 pumps all the way to the floor, through each calliper should be enough, but you'll see the colour change of fresh fluid.
No harm in getting 2 lts though and doing the sequence twice.
Dot 4 will be fine.
But Dot 5.1 is an upgrade with a higher boiling point...but I seem to remember is is more hygroscopic so will need changing more often than Dot 4 can be left for (should still be fine for every 2 years though)
I'd use Dot 5.1 as it's compatible with the current Dot 4.
Don't use Dot 5.0 though...it's not compatible with Dot 4.
Just FYI everyone, DoT 5 is a silicone based brake fluid, it won't damage your paint. DoT 4 and 5.1 are mineral based and will strip off the paint.
You can use DoT 5.1 but you will need to flush out the system with methylated spirits first.
You can use DoT 5.1 but you will need to flush out the system with methylated spirits first.
shineydave
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we had a look at fluids a while back when upgrading Clives front brakes, our conclusions where that Dot 5.1 was compatable with Dot 4. Dot 5.1 was basically the same as 4 but lighter to take advantage of increased speed of cycling the ABS pump when you lock a wheel up. since DOT 4 was the standard fluid used by Audi we couldn't find any reason to change. the only other thing we did was search for the one with the highest boiling point, we found it could vary over a range of around 200 degrees from the worst to the best. some of the better DOT4 fluids had boiling points much higher than Dot 5.1 fluids dispelling the myth that 5.1 has a higher boiling point.
Dot 5 as stated above is silicon based and not compatible with either 4 or 5.1, i believe this is the one that you need to flush the system through before refilling it as it's not compatible with anything else. Dot 5 as stated above will absorb moisture from the atmosphere quite quickly with the potential to cause vapour lock. it's aimed at track cars and should be changed every 6 months to reduce the risk of the vapour lock issue.
personally i'd check the specs and go for whichever DOT4 fluid had the highest boiling point.
Dot 5 as stated above is silicon based and not compatible with either 4 or 5.1, i believe this is the one that you need to flush the system through before refilling it as it's not compatible with anything else. Dot 5 as stated above will absorb moisture from the atmosphere quite quickly with the potential to cause vapour lock. it's aimed at track cars and should be changed every 6 months to reduce the risk of the vapour lock issue.
personally i'd check the specs and go for whichever DOT4 fluid had the highest boiling point.
Dave, DoT5 brake fluid is non-hygroscopic meaning is does not absorb water, a lot of classic car owners prefer it as their cars stand idle for long periods and the fluid retains its efficiency. I think maybe you got them mixed up a bit.
Dave B
REALITY?.... WHERE AM I AGAIN?.... WHO AM I AGAIN?
Cheers guys!
Im looking at using ATE Super Blue will I need to purge the system first or can i do a thorough bleed through?
ATE Super Blue Affordable high performance brake fluids that have both a high dry boiling point (280 deg C) and a high wet boiling point (198 deg C), but without being excessively hygroscopic. What this really means is that these fluids do not readily absorb moisture like most high performance fluids. Moisture in your braking system can be costly requiring a complete braking system overhaul! A must for any car equipped with modern high friction brake pads.
Also, the blue tint of the fluid makes bleeding brakes easy! You can easily tell when you have flushed out the older fluid.
If you're thinking of replacing your brake lines, pads or just want to get better performance out of your stock brake system, this is a great product to make bleeding your brakes worth your time. Don't replace your brake fluid with stock fluid if you have the opportunity to go to a performance brake fluid like the ATE Fluid.
Dave
Im looking at using ATE Super Blue will I need to purge the system first or can i do a thorough bleed through?
ATE Super Blue Affordable high performance brake fluids that have both a high dry boiling point (280 deg C) and a high wet boiling point (198 deg C), but without being excessively hygroscopic. What this really means is that these fluids do not readily absorb moisture like most high performance fluids. Moisture in your braking system can be costly requiring a complete braking system overhaul! A must for any car equipped with modern high friction brake pads. Also, the blue tint of the fluid makes bleeding brakes easy! You can easily tell when you have flushed out the older fluid.
If you're thinking of replacing your brake lines, pads or just want to get better performance out of your stock brake system, this is a great product to make bleeding your brakes worth your time. Don't replace your brake fluid with stock fluid if you have the opportunity to go to a performance brake fluid like the ATE Fluid.
Dave
Ess_Three
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No, you will be fine with Super Blue.
No flushing required.
Simply pour into the reservoir and pump out through the MS and each calliper in turn, until you see the fluid go from dirty amber to blue. Job done.
Shineydave is correct in what he says about boiling points of Dot 4 vs Dot 5.1...although your local motor factor is likely to have dot 5.1 with a higher boiling point than some of the rarer Dot 4s.
I tend to use some AP Lokheed 5.1 stuff that's cheap...far cheaper than the high boiling point dot 4 stuff...so use what you like, but try to get the one with the highest boiling point if you want to track the car.
On the road, I doubt it will matter.
No flushing required.
Simply pour into the reservoir and pump out through the MS and each calliper in turn, until you see the fluid go from dirty amber to blue. Job done.
Shineydave is correct in what he says about boiling points of Dot 4 vs Dot 5.1...although your local motor factor is likely to have dot 5.1 with a higher boiling point than some of the rarer Dot 4s.
I tend to use some AP Lokheed 5.1 stuff that's cheap...far cheaper than the high boiling point dot 4 stuff...so use what you like, but try to get the one with the highest boiling point if you want to track the car.
On the road, I doubt it will matter.
shineydave
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Chris you're right, it's not hygroscopic and i did get confused. because it doesn't absorb moisture any that gathers in the system falls to the lowest part of the system, usually the calliper. this is then easily boiled during normal braking causing the vapour lock hence the reason it should be changed regularly
shineydave
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i had to search for the info and weed through a lot of chaffe to get to the nuts and bolts of it all. one camp say DOT 5 is a better fluid because it doesn't absorb moisture but that is based around the premis that you don't get moisture in the system in the first place. now you can check this by taking the cap off your master cylinder and i can almost guarantee there will be condensation on the underside of the cap. this is what gets into the system, if you can prevent that forming then you can comfortably change to DOT 5 and forget about it but there is a caveat. i found a piece on wikipedia that said you can't just flush the system through as all the solvents that will effectively remove DOT 4 and DOT 5.1 will also effectively rot the seals in the system. if you don't remove all the traces of DOT 4 or 5.1 then it creates a reaction with the DOT 5 that creates a kind of sludge.
so to do it properly you have to strip the entire system, dissassemble the components and clean them with brake cleaner.
i think that whilst DOT 5 is clearly a superior fluid it's really only usefull if you're going to be building a brake system from scratch AND you can prevent the ingress of condensation.
just for info i found a piece too on how to tell the condition of your existing fluid by visual inspection. it says that as the water is absorbed the fluid will go steadily darker in colour, once it gets darker than honey it should be replaced. if it's black then you have seal failure and the system should be stripped and inspected to find the failure.
can i go to bed now?, lol
so to do it properly you have to strip the entire system, dissassemble the components and clean them with brake cleaner.
i think that whilst DOT 5 is clearly a superior fluid it's really only usefull if you're going to be building a brake system from scratch AND you can prevent the ingress of condensation.
just for info i found a piece too on how to tell the condition of your existing fluid by visual inspection. it says that as the water is absorbed the fluid will go steadily darker in colour, once it gets darker than honey it should be replaced. if it's black then you have seal failure and the system should be stripped and inspected to find the failure.
can i go to bed now?, lol
