Problems after changing brake fluid

[celox performance]

I've changed my brake fluid to the Castrol SRF. Where before I had a hard pedal where the bite was sharp and right at the very top, perhaps too sharp, the pedal is now more spongy since changing the fluid and there's a couple of inches of travel in the pedal before I get any bite.

Before I changed the fluid the brakes they were either on or off with no progresion and since changing the fluid they're more progressive now but i've lost the initial bite and have a softer pedal. I've bled the brakes myself twice now and took the car to National Tyres where they've also bled it again but it's exactly the same :? . They suggested that I try a power bleed using a bleeding machine that connects to the car's battery, but the one National Tyres use won't fit the reservoir cap.

Any suggestions as to what it could be at all? I can't see why changing the brake fluid to a better fluid would cause the pedal to be softer than the old fluid, I would have thought i'd have a firmer pedal if anything?

 

[Chris-DC5]

You have got air in the system mate.

You said in the other post that you let the system drain for about 30 mins, Bad idea.

When we say bleed we mean get rid of the old fluid by pumping out the old fluid and putting new in.

You will just have to keep bleeding untill you get all the air back out.

Cheers

 

[C&S Evo7]

still have air for sure, have you done the correct sequence on the front calipers

 

[lockwood77]

What is the correct sequence for the front calipers? Outside nipple first, inside nipple second?

 

[celox performance]

So I shouldn't have left the fluid to drain by itself then

The sequence I used is:

Bleed the near side rear wheel first,
then the off side rear wheel,
then the near side front wheel
then the off side front wheel

National Tyres used a different sequence and they had no luck either.

 

[lockwood77]

No, force the old fluid out with the new, don't drain it. SRF is a bit of a different colour to other fluids, so it's fairly obvious when you've forced the old stuff out.

What sequence did you do the two nipples on each front caliper?

You should start with the wheel furthest away from the reservoir, I always get confused by NS/OS (is near side the driver side?), but that would be passenger side rear first, then driver side rear, passenger side front, driver side front.

 

[celox performance]

I'm fed up with cars! :lol:

I've just booked it in with TDi tomorrow morning and while it's there they're going to replace the gearbox oil. It's been suggested that there could be air in the ABS system too and i'm not messing around with it myself. The track day i've got booked at Donny isn't looking very hopeful at the moment and i've still got plenty to do

 

[alucardo]

No, force the old fluid out with the new, don't drain it. SRF is a bit of a different colour to other fluids, so it's fairly obvious when you've forced the old stuff out.

What sequence did you do the two nipples on each front caliper?

You should start with the wheel furthest away from the reservoir, I always get confused by NS/OS (is near side the driver side?), but that would be passenger side rear first, then driver side rear, passenger side front, driver side front.

Near Side is passenger side so rear left first and so on....

 

[Dixcelbrake]

one quick trade secret - Boil your brake oil first before you bleed it. Hot oil are alot more easier to bleed.

 

[logik]

one quick trade secret - Boil your brake oil first before you bleed it. Hot oil are alot more easier to bleed.

How would one boil their fluid before bleeding it?

 

[dave c]

one quick trade secret - Boil your brake oil first before you bleed it. Hot oil are alot more easier to bleed.

How would one boil their fluid before bleeding it?

140mph - 0mph a couple of times should help you get the idea i'm sure

 

[celox performance]

After taking it to TDi today I now have a firm brake pedal and have had the gear oil replaced with Redline 70w80, so that's killed two birds with one stone

Looks like my track day is still on :green:

 

[Chris-DC5]

one quick trade secret - Boil your brake oil first before you bleed it. Hot oil are alot more easier to bleed.

How would one boil their fluid before bleeding it?

140mph - 0mph a couple of times should help you get the idea i'm sure

So when we bring our cars to your place to have a service/fluid change etc you are going to take our cars out and drive/rag them and boil our brake fluid!!!

What a load of rubbish, :xtsk:

 

[celox performance]

Or maybe he'll put a kettle element in the brake reservoir and boil it that way :xlol:

 

[Dixcelbrake]

We just put it in boiled water for 10 mins before we fill up :wink:

 

[mikegsi]

Glad to hear it's sorted mate!!

On another note, top tip of the day.......

"if your not sure........ Don't!!!!"

 

[12T]

What was the problem celox how did they fix it?
i think i have the same problem :-k

 

[celox performance]

There's a sequence you have to use to bleed the front 4 nipples and they also used a box to hold the fluid in. Myself and National Tyres just stuck our fingers over the nipples and did it through sight, which isn't the method needed for Brembo brakes.

 

[lockwood77]

I was talking to Steve at TDI North about bleeding the brakes yesterday, as I had some air issues after servicing a rear caliper and changing the fluid. Turns out it was just air in that caliper, there must have been more floating to the top when I thought it was running clear.

Steve's method is outer nipples first, inner ones second, although he doesn't think it really makes much difference. I did mine the other way round (twice) and there doesn't seem to be any air in there.

I used my old man's Eezi-Bleed kit to do mine - sadly the top doesn't fit on the DC5 reservoir, so we still had to pump the pedal, but it comes with a tube you clip to the nipple and a one-way valve on the other end, so air isn't sucked back in when you take your foot off the pedal.