I've got around to getting the brakes off my sierra. The haynes manual tells you how to bleed the brakes but not how to drain them.

What do I need to do? Just disconnect the hose and suck on the end?

I went to get the caliper off. Use a 7mm allen key said the manual so I check all the allen keys I have.

2mm
2.5mm
3mm
3.5mm
4mm
5mm
6mm
8mm
10mm

So I check with a few mates. Everyone has six and eight but no seven.

Brainwave. I check the allen key thingy I bought for my push bike which I forgot about before.

4mm
5mm
6mm
8mm

Ahggh!

My drill! That has a couple of allen key attachments.

6mm
8mm

Noooooo!

What is it with 7mm allen keys? They seem to be rarer than hens teeth. I did try both the six and the eight just in case but they were no use.

Why not carefully file/grind the flats on an 8mm allen key down to get to 7mm AF? I did that with a 2mm key to get down to some american size for my RC helicopter. Worked a treat. You could even get it hardened afterwards if you know the grade of material the key is made from!

as for draining brakes, then so long as the cap is off the fluid resevoir, then the brake fluid should drain out under gravity if you disconnect the caliper pipe. you might want to leave it overnight 9draining into a suitable container) to get every last drop out. or you could probably use one of the pressure brake bleeders to force it out.

hope that helps!
Andy

I believe there is a special tool for this , I had one by Draper for my old Escorts, large allen key with a plastic grip.

Of course I could be wrong!!

Avalible from draper (and others With identical items) are sets that consist of 10mm sockets and bits that fit in them. The sockets fit 3/8 and 1/2 inch. The bits in my set include hexagon (allen), TX-star and XZN.

the importan bit is that it contains a 7mm hexagon that can fit on a 1/2 inch ratchet.

Draper list price is about £30

A draper alternative is a 30 peice allen key set for about £15 list that incleds a 7mm (15 metric and 15 imperial)

[Edited on 19/4/05 by clbarclay]

Halfords sell Allen sockets singly.
I bought one for the same job on my Audi - I think it was 7mm

they also sell 7mm brake wrenches (with a long blue handle) for about 4 quid in, *ahem* halfords.

Cheers guys. Thats all helpful stuff. I'll pop along to halfords and see if I can get a 7mm one.

One more thing. The brake fluid is corrosive. Does this mean I can't use spare plastic bottles I havelying around to drain it in?

Glass would be OK though right?

Assuming the brake pads were replaced recently are they likely to have asbestos in them? Any special way I'm supposed to dispose of them?

[Edited on 19/4/05 by Monkey Man]

hi mate. I think you could be being a bit technical here! asbestos is only real bad news when there is free dust floating about - hence even brake dust wont do much damage, cos its all firmly stuck to your nice shiny wheels! Stick em in the bin

As for corrosive brake fluid, its not that bad - bad for paint, but ive had it all over my hands with no ill effects Any plastic will be fine

You might be able to guess that i dont work for the HSE, hence my advice is only advice

Just what I wanted to hear. Cheers!