Changing Front Calipers

[fearofweapons]

(following on from my new discs thread....)

I checked the brakes on each wheel over the weekend and each side was rubbing - so pistons not retracting fully.

I whipped the pads out and started to clean the callipers/pistons - the pistons did have a ring of 'crud' around the top 1/8th or so and this appeared to be hampering proper retraction.

On inspection I noticed that the o-rings were perishing - they were poking up and torn. One piston, near side front appeared to be missing a metal ring of some sort (sorry I do not know the correct term for each discreet part of the calliper)

This was not really what I wanted to find but at least I found it.

Looking at cost of parts and time available I am going to just replace the callipers on both sides - parts on order.

My question is around removing the callipers without draining all the fluid from the brake system.

Am I correct in thinking I clamp a pair of pliers (?) onto the flexible hose to prevent fluid loss?

What would others recommend?

My intended order of activity is

• to clamp both flexible brake hoses
• swap the callipers for new ones
• refit the hoses
• refit pads etc.
• bleed and top up brake fluid as required
• go for tentative test drive....

Any advice gratefully received. I did do a search for 'callipers' but did not find a post that really covered my (basic) question.

cheers,

Rich T

[Puffernutter]

The principle seems fine, although I'd just do one at a time. Clamp, remove, replace, bleed. Then do the other side.

Cheers

Peter

[reb78]

I don't know if the others will disagree here, but I never bother to clamp the hoses. I always have this worry that I will knacker them quicker if I put a tight clamp on there. I just take the end off of the caliper and let the fluid drain into a container. Then bleed as usual once the job is done. You replace all of that old fluid that way too.

[ukspike]

Only use a proper brake hose clamp not a pair of locking pliers, they will damage your rubber hoses, and I would do one caliper at a time, bleeding each one separately, before moving onto the other side, checking oil level all the time.

[Tanuki]

I never bother with hose-clamps either: I've got a female brake-union and ball-bearing.

Undo the metal-feed-pipe-to-caliper union; pop pipe out of caliper, drop ball-bearing into large end of female brake-union, and screw it on to the end of the pipe.

Even when only finger-tight the ball bearing is pressed against the end of the pipe with sufficient force to prevent the escape of any fluid.

Also, by bunging up the end of the pipe it stops any dirt/rust/grot getting in there.

--Tanuki.

[Aragorn]

i'm with reb. Dont crimp the hose, especially if they are braided ones. Put a plastic bag over the reservoir cap and refit it to block the air hole (stops it draining out), then just undo the caliper. Or if your quick and feeling lazy, just whip the hose off and stick it into the new caliper quickly.

Take the opportunity to drain the reservoir (dont just pour your new fluid into the reservoir with the grotty old stuff!), and fully flush the system thru with new fluid if its not been done recently. I like using ATE Blue for this as you can see the fluid come thru in the correct color and you know its properly bled. You can then switch back to normal fluid (or ATE Typ 200 if you want to stay in the same family) next time you change the fluid and you get the same effect, going back to yellow when the new fluid comes thru.

[Bowie69]

I made up two plugs for brake hoses, flare the end of a piece of brake pipe, put it through an M10x1 female fitting and then squash the end in a vice.

Now I remove the hose, screw it on (even hand tight is enough as there is no pressure) and it's sealed.

I have stainless hoses so crushing isn't an option

If you haven't got a flaring tool, your local garage could make them up for a tenner I would have thought.

[fearofweapons]

All,

many thanks for the replies. I did fully bleed and renew my brake fluid <12 months ago so was not looking to do it again so soon.

I was wary about clamping the hoses due to potential for damage, I like the idea of the end cap as a way to prevent fluid loss and ingress of foreign matter. The bag under the cap I had also considered as a way to slow down fluid loss.

Once again many thanks - parts due on Wednesday so hopping for a nice evening.

cheers,

Rich T