Flexible brake hose

Post by **smh582003** » Wed Dec 26, 2007 1:19 pm

I am trying to change the brake cylinders on the front of my car and have managed to do one. I am having trouble getting the flexible brake hose off. I think I will need to replace it but my problem is I have clamped the hose to stop the fluid but if i go ahead and take the whole hose off what should I do about the fluid ? Just let it all come out and bleed the whole system?Is this the best way?
Thanks
Steve

Post by **8009STEVE** » Wed Dec 26, 2007 1:36 pm

Undo the master cap, cover the plug in cling film, and replace the cap. This might stop the fluid seeping out, but you will still have to bleed the system after changing the hose.

Post by **MoggyTech** » Wed Dec 26, 2007 2:59 pm

Assuming you are using DOT 4 standard mineral brake fluid and not silicon Dot 5 then it's a good idea to flush the entire system anyway.
Standard brake fluid should be renewed every two years to prevent moisture in the fluid eating away the brake components. If in any doubt about the condition of the flexi hose then replace it. If it's simply seized into the wheel cylinder, one trick is to undo the wheel cylinder from the backplate, Firmly clamp the metal end of the flexi hose with vice grips, push the pistons out of the wheel cylinder, place a screwdriver through the wheel cylinder, and use the screwdriver to rotate the wheel cylinder off the hose.

Single circuit brakes = take no chances.

Post by **simmitc** » Wed Dec 26, 2007 4:41 pm

I don't like the sound of putting a screwdriver through the cylinder, suggests potential to damage the bores which could lead to failing seals.

Because the master cylinder is mounted in the chassis leg, it is below the level of the connection between copper and flexible pipes, and so the entire system will not drain when you remove the flexible hose. However, you will still need to bleed the system, and you do need to change the old style fluid regularly.

To remove the flexible hose, first undo the copper pipe from the flexible, then remove the large nut holding the flexible to the body, and lastly remove undo the flexible from the cylinder. Of course, if you're replacing the flexible hose then you could just cut the old one to make things easier.

If the hose has been in place for a ong time then you may need plenty of penetrating oil to free the retaining nut.

Post by **bigginger** » Wed Dec 26, 2007 4:52 pm

IME, you may have to cut the hose and replace both it and the cylinder

Post by **MoggyTech** » Wed Dec 26, 2007 7:39 pm

I don't like the sound of putting a screwdriver through the cylinder, suggests potential to damage the bores which could lead to failing seals.

Ah but the person in question is replaceing the cylinders anyway so not an issue in those circumstances.

Post by **bmcecosse** » Wed Dec 26, 2007 9:26 pm

If you have 'clamped' a rubber flexi hose - you should renew it! My experience in the past has been that they start to 'balloon' after doing that -with failure just round the corner. Just be ready with a little plug to stick on the end of the brake pipe when you take the flexi off. Helps too if the car is jacked up so the part you are working on is higher than the master cylinder! Yes - this assumes the car has not been fitted with a remote reservoir!