Remove Caliper - Fluid Loss

[pbar]

I always thought the usual method of preventing fluid loss when removing a caliper,etc. was to clamp the flexi brake hose, but I've read online that all you need to do is wedge the brake pedal half way down, as this places the master cylinder seal past the port and no fluid will be lost. It's like putting the end of your finger over a straw with water in it, fluid can't escape.

Never hear of this technique before, sounds much better as I've never been comfortable squashing brake hoses, anyone tried this method?

[nemo]

Hello.
I`ve personally never heard of that method so can`t comment.
You can put a piece of thin polythene or silmilar between the reservoir and cap (which has a tiny air hole). This will create a partial vacuum and shuld limit fluid loss to just a few drops - the less air in the reservoir the better.
Never had a problem myself, or heard of a problem with the hose clamps though. I do prefer the old `bar` type (Sykes Pickavant?) rather than the ones which resemble side cutters as they have a more gentle, rounded `squashing` action.

[Paul G]

I always thought the usual method of preventing fluid loss when removing a caliper,etc. was to clamp the flexi brake hose, but I've read online that all you need to do is wedge the brake pedal half way down, as this places the master cylinder seal past the port and no fluid will be lost. It's like putting the end of your finger over a straw with water in it, fluid can't escape.

Never hear of this technique before, sounds much better as I've never been comfortable squashing brake hoses, anyone tried this method?

Paul - I wouldn't bother. It would be about as effective as the other old wive's tale of putting clingfilm over the reservoir.

Nemo is right that the most effective way is to use a proper hose clamp but if you haven't got one wrap several layers of masking tape round and round the hose then use a molegrip (not set too tight) to grip the hose. The masking tape will stop the hose being damaged.

[pbar]

Thanks Paul, as usual traditional old school methods are the best then, I just always worry when clamping them that the inner will collapse or something and never recover, especially on old ones.

I do have a caliper to remove on a vehicle, or rather hack off as the unions are seized. Do you know please, is it acceptable from an MOT point of view, to join brake pipes? specifically the small copper one which runs from the caliper to the flexi hose. I hope to cut it close to the caliper and put a new flare and nut on, but Just wondering in case it ends up too short.

[nemo]

Pbar,
I`d say as long as theyre proper unions it shouldn`t be an issue. But wouldn`t it be just as easy, and neater, to just make up a new pipe, on the bench rather than doing in-situ? (But then, I do appreciate that depends on what the other ends like.)

[pbar]

No because it is seized at the flexi also, and that is seized at the next union, etc. So it means chasing it further up the vehicle and changing a lot, which I can do but right now I'm wanting something quicker as I need to get it moving.

Don't want to join it though if the tester says no you can't do that!

[Peter-S]

You will still lose some fluid and need a cloth to hand but you can disconnect the pipe at MC and fit a bleed nipple in its place.

[pbar]

Thanks Peter, I would need to bleed the whole system then though I assume, whereby just disconnecting at the caliper means hopefully just bleeding that one when replaced.

Anyone know for certain if joining the pipes, as mentioned above, is MOT allowable?

[Mc Tool]

If you have a double flaring tool and some new nuts you could make a new tube ....and unless your sure the rubber hose is serviceable get a new one .
I also view wee jobs like this as an opportunity to flush a bit of fluid thru the system ,dont have to bleed the whole thing but giving each wheel a couple of pumps moves the fluid on a bit .
As far as clamping brake lines ......not for me , specially metal braided lines. I think its sorta ok if one has some appreciation of brake hose construction and the potential of crush damage .......but sadly we aint all brilliant ....sooooooo

[pbar]

Thanks, I can't do what you suggest for reasons I've explained. I hope to be able to cut the pipe close to the caliper, fit a new nut and flare in situ, and replace the caliper.

[nemo]

If you cut right at the union you`ll only lose 1/2" of pipe at the most so it shouldn`t be a problem ( assuming the pipe doesn`t travel in a straight line F - C, they`re usually a bit of an `S`which gives a bit of leeway)

[pbar]

Thanks, yes that's what I thought, hopefully only lose half an inch or so and it is indeed S shaped so I'm thinking I should be able to expand the shape by that amount to fit a new nut and flare. Here's hoping!

[Paul G]

Paul, if you get stuck PM me your address and I'll make you a new pipe F.O.C.

P.

[Mc Tool]

yeah , I see what your up to now .
How long is the flare nipple ? I had a notion they are about ¾" long .
Is there any way you could heat the caliper .....bit of crc

[Bug]

It would be about as effective as the other old wive's tale of putting clingfilm over the reservoir.

Call me an old wife then, as I've done that countless times since I first started back on my old Mk1 Escort.
Fill the reservoir to the brim then a poly bag under the cap and do it up tight.
Basic physics seems to have always worked a treat for me.

[Paul G]

Well I stand corrected but I've still never had success with that method. Not much use on a master cylinder reservoir cap with a fluid level indicator I would have thought,

[Bug]

Well I stand corrected but I've still never had success with that method. Not much use on a master cylinder reservoir cap with a fluid level indicator I would have thought,

Yeah, you can still do it with a bigger bit of poly bag so it goes round it.
The system has to be sealed to stop leaks, so that is why there is an air vent in the top to allow for movement of the fluid as you brake, or as pads wear etc. So if that is the only way air can get in, blocking it works. However, it is best to fill the reservoir to the brim first as the air gap can expand and compress and thus let some fluid escape.

[pbar]

Paul, if you get stuck PM me your address and I'll make you a new pipe F.O.C.

P.

You are a real gent, thank you Paul, that offer is very much appreciated. It's not a Capri job I'm doing by the way, it's another vehicle of similar age.

Latest update - I cut the pipe close to the caliper, and was able to drill the fixing out of the caliper whilst on the bench. Put a new flare on the cut off pipe, but just can't stop it leaking when the caliper is back on and connected up.

Tried a couple of flares but I only have one of those cheaper clamp type flare tools though, and they only do SAE flares, whereas I'm pretty sure the vehicle has DIN spec. and although they are similar (and often SAE will work with both types) I think I might have to invest in a DIN flare tool and try that.

[pbar]

Yeah, you can still do it with a bigger bit of poly bag so it goes round it.

Hi Martin, do you mean allow the poly/clingfilm, etc. to 'sag' underneath the level indicator/gubbins, so you have a sort of U shape in effect, which then comes up and out under the cap/threads.

[Bug]

Yeah, you can still do it with a bigger bit of poly bag so it goes round it.

Hi Martin, do you mean allow the poly/clingfilm, etc. to 'sag' underneath the level indicator/gubbins, so you have a sort of U shape in effect, which then comes up and out under the cap/threads.

Yes. I wouldn't trust clingfilm not to break and leave bits in there though. I used to cut open a freezer bag so it was just one thickness.