Fitting new brake master cylinder / reservoir

[Asian Boss]

To one of my fucked XLs. I got a complete unit which looks pretty easy to fit. Fingers crossed the bleeding is easy too.

Will those washers seal it to the brake line or will it need copper ones?

Brake (Medium).JPG (486.46 KiB) Viewed 854 times

B2 (Medium).JPG (449.41 KiB) Viewed 854 times

[cheb]

If they are what's supplied with it then I'd give them a go. At worst you can anneal and reuse the old ones, heat them red hot with a blow torch. Quenching optional.

[KungFooBob]

I'd use it as an opportunity to fit a nice new shiny braided hose, which will come with new banjo bolts and washers.

You could try those in the picture, they might work. Or if the ones on the bike at the moment are copper, you could anneal them.

[Asian Boss]

Cheers chaps.

I'm kind of keen to stick with the (ancient!) original rubber hose. From memory braided steel ones were a much smaller diameter and a right cunt to bleed as a result.

The bike rarely exceeds 45mph and the front brake is never going to be anything other than fairly gentle.

[KungFooBob]

Depends how old it is.

Rubber hoses degrade. If you read the manual it will suggest replacing them every 4-5 years (which no one ever does). The rubber brake hoses on my 98 BMW K1200 were fucked and have been replaced.

I would 100%, without a doubt, whenever budget allows, replace standard hoses with braided ones (yes I know they're still rubber inside).

[Asian Boss]

I suspect you're absolutely correct on the timing thing, I imagine the current hose is well past its best before date.

I'm not totally convinced with the always fit braided hoses thing, the Japanese rarely do from new and for that reason alone I question their value. Plus the small bore thing (if that's true). Maybe the Js think people will replace the OE ones every five years!

[KungFooBob]

They were standard fitment on my Triumph and Moto Guzzi.

I put them on my Blade too.

Back in 1999/2000 when I bought a new R6 all the rags said not to fit braided hoses as the 'awesome' bluespots would be too keen and have you off.

To race in the UK with the ACU, you have to have braided hoses, iirc.

[DefTrap]

I've never had problems bleeding braided ones

[Asian Boss]

I've never had problems bleeding braided ones

I haven't either. I just read about it and pappered mesen.

[Druid]

I suspect you're absolutely correct on the timing thing, I imagine the current hose is well past its best before date.

I'm not totally convinced with the always fit braided hoses thing, the Japanese rarely do from new and for that reason alone I question their value. Plus the small bore thing (if that's true). Maybe the Js think people will replace the OE ones every five years!

I think cost might be the deciding factor in the choice of OE hoses

[Asian Boss]

The new master cylinder / reservoir hose connection is on the side rather than the front and doesn't fit the existing hose well. I think it could be time for a braided steel hose (as suggested!).

In my mind they were expensive items, perhaps due to PB ads in the 90s... looks like you can get one for 15 or 20 quid from t'Bay. I do wonder if it will be a cunt to bleed but I'll cross that bridge when I come to it. I certainly can't get it to bleed with the current hose stretched into place.

[Le_Fromage_Grande]

I think the pre made braided steel hose I bought to use for the clutch on my Kawasaki was about £6, I thought as it's a clutch it doesn't really matter if it fails, it's been fine.

And bleeding - take your time, slowly pump the brake lever until you get no more bubbles at the top before worrying about the bleed nipple on the caliper.

[The Spin Doctor]

I suspect you're absolutely correct on the timing thing, I imagine the current hose is well past its best before date.

I'm not totally convinced with the always fit braided hoses thing, the Japanese rarely do from new and for that reason alone I question their value. Plus the small bore thing (if that's true). Maybe the Js think people will replace the OE ones every five years!

It's easier to sport damage to a rubber hose IMHO.

I had the front brake fail when a slightly too short braided hose wore through on a second hand bike I'd bought a few weeks earlier. The bike had been MOT'd a couple of days earlier and neither I not the MOT guy spotted any damage. As soon as the braiding failed, the thin liner popped and I got a faceful of brake fluid braking for a t junction at the bottom of a hill.

[DefTrap]

For ss hoses, I've used both HEL and Goodrich, both fine.

[Druid]

My easy bleeding tip:

Take the caliper off and pump the pistons almost all the way out. Bolt your new braided hose to the new m/c, undo the hose from the caliper and bolt the new hose to it. Fit the new m/c to the bars and push the pistons all the way in to the caliper. This will force the brake fluid into the new brake line and up into the m/c reservoir. Refit the caliper and bleed with new fluid.

Oh yes, new copper washers on both banjos

[iansoady]

.... and anneal the copper washers whether old or new. New ones sat on a shelf do harden.

[Le_Fromage_Grande]

My easy bleeding tip:

Take the caliper off and pump the pistons almost all the way out. Bolt your new braided hose to the new m/c, undo the hose from the caliper and bolt the new hose to it. Fit the new m/c to the bars and push the pistons all the way in to the caliper. This will force the brake fluid into the new brake line and up into the m/c reservoir. Refit the caliper and bleed with new fluid.

Oh yes, new copper washers on both banjos

That's a good tip, hadn't thought of that

[Mr. Dazzle]

FWIW those washers are way more common than copper ones in industry. I can't remember the generic name for them, I call them "Dowty Washers". I think they're called sealing washers generally.

They should be better than copper, with the usual caveats that the faces are clean, you've got the right sized bolt etc. The idea is that you can do them up as tight as you like and you'll never go past the optimum seal. Once you've squashed the rubber flat (see how it sticks out a bit) you're bottomed out on the steel and further tightening has no more effect on the seal.

Properly sized and fitted Dowtys will hold thousands of PSI, they're standard fit on industrial hydraulics, aircraft landing gear, car active suspension etc.

Edit: Bonded sealing washers! That's the badger.

[Skub]

Dowty washers have a rubber seal in the inside diameter. We used them a lot to waterproof field units.

[Mr. Dazzle]

Dowty washers have a rubber seal in the inside diameter. We used them a lot to waterproof field units.

Yeah thats what the pic shows? Unless my eyes is playin' tricks?