A610 brakes

My rear calipers recently started sticking very badly, and someone in the other thread recommended trying Bigg Red for a rebuild. Just got my calipers back today haven't actually bled the fluid and tried them yet, but they certainly look good...

Before




After

They look great ...but ...have you been feckin off-roading again

Well, er... here's where I work, 20 miles of lovely muddy country roads there and back each day:

Finally got around to bleeding them and reconnecting the handbrake and.. fluid leaks from where the hoses screw into the caliper. Anyone know if there's meant to be a washer or something in there? I'm sure there was nothing when it came apart, but the hoses do not screw in all the way - there's still thread exposed when fully tightened, and fluid is coming up it.

Also, does anyone know why there's a big yellow sticker on the fluid reservoir saying "DOT 5 only", when the cap says "DOT 3/4 only"? Pretty sure it should be DOT 4...

It is a taper thread so should tighten and seal before bottoming out .Check you are not cross threaded or there is paint/shite in there ??
DOT 5 is the spec .

Also, does anyone know why there's a big yellow sticker on the fluid reservoir saying "DOT 5 only", when the cap says "DOT 3/4 only"? Pretty sure it should be DOT 4...

I suspect the previous owner filled up with Dot 5 and put the sticker on. But you might wish to read this info:-

­"As a DOT3 or DOT4 brake fluid absorbs water, its boiling point decreases. It can absorb water from the air, which is why you should avoid opening your car's brake fluid reservoir. For the same reason, you should always keep containers of brake fluid tightly sealed.

DOT5 fluid does not absorb water. This means the boiling point will remain relatively stable, but it also means that any water that does get into your brake system will tend to form pure water pockets, which could cause brake corrosion"

Another point nagging me about this, if I remember it rightly, someone here might be able to correct me. Do you not have to have different seals for Dot 5, as the standard seals don`t like the Silicone based fluid ?????

I did tighten both hoses as much as I was physically able, but will retry. I did triple check for debris/cross threading.

Bit worried now because I refilled with DOT 4. AFAIK the car was designed for 4, not 5 - the cap says 3/4 and the fluid I used said it was for GTA/610. The two are incompatible, but hopefully it shouldn't damage any seals. I am flushing it right through all 4 brakes anyway so all the previous fluid should be gone... or do I now need to bleed the clutch too?

... or do I now need to bleed the clutch too?

Yep. If there is uncertainty about what it was filled up with before..... better be safe than sorry. In fact I would do the clutch then do the brakes again to make sure all contamination has been flushed away..

Dot 5 ....

[stephendell]

NEVER put DOT 5 brake fluid in an A610

DOT 5 is silicone fluid and should not be used with ABS systems.

Silicone fluids absorb air instead of water and are slightly compressible. Another characteristic of fluids with dissolved air is that abrupt changes of pressure can result in the release of more air bubbles into the fluid, an effect similar to having a poorly bled system. These abrupt changes can occur in ABS valves and this is, I believe, why DOT 5 fluid is not recommended for use in vehicles fitted with ABS.

In addition if you have mixed glycol and silicone any water will get trapped in the lowest part of the system and cause corrosion.

This is one of the reasons why we think the ABS doesn't work in the majority of RHD A610's because some bright spark put DOT 5 labels on the reservoirs. So most will have had mixed fluids at some point due to owners confusion.

Use DOT4, DOT 5.1 or infact anything except DOT 5.

There is a special flud for ABS systems made by ATE called SL6. It is DOT 4 Rated. ABS specific fluids have a lower viscosity as required by most ABS systems.

Personally I use ATE super blue because it has a higher boiling point and prevents clutch fade if you ever drive the car really hard (eg at a proving day).

Why does it state DOT 5 in the 610 manual ?

In addition it also states SAE code and a special not ( Brake fluid must be approved by design office )


Document Number: J1703
Project Number:
Project Initiation:
Revision Number:

Title: Motor Vehicle Brake Fluid

Issuing Committee:
Brake Fluids Standards Committee

Scope:
This SAE Standard covers motor vehicle brake fluids of the nonpetroleum type for use in the braking system of any motor vehicle such as a passenger car, truck, bus, or trailer. These fluids are not intended for use under arctic conditions. These fluids are designed for use in braking systems fitted with rubber cups and seals made from styrene-butadiene rubber (SBR), or a terpolymer of ethylene, propylene, and a diene (EPDM).

special design consideration notes always bother me ......there must be a reason ..

This might throw some light on the subject :-

I know all that but .......special design consideration and DOT 5 is specified in the manual .Maybe the ABS system is designed for 5 ??