Author Topic: Shimano Hydraulic Brake fitting help. (Read 2708 times)

rafletcher · « **on:** 19 February, 2018, 12:48:03 pm »

So, I bought a nice new L/H shifter. It came with a short length of hose attached, with a straight union fitting allowing the hose to be extended, like so

IMG_0092 by Richard Fletcher, on Flickr

It also came with a nice new calliper with a length of hose attached. Unfortunately and rather annoyingly the combined length of hose is insufficient to reach from shifter to rear calliper....

IMG_0094 by Richard Fletcher, on Flickr

So I have two options as I see it. Use a new piece of hose and run it from the straight union on the short hose already attached to the shifter (which comes with nut & olive and a plug) to the rear calliper, removing the too-short calliper hose and using a new olive and nut there, or I can replace the whole length of hose.

My preference is to replace the whole length as then I only have two joints rather than three.

Either way I'll have a length of empty (of oil) hose when I start. Should I try an pre-fill the hose before fitting (seems fraught with difficulty and potentially very messy) of should I just fit it empty and bleed through afterwards?

I also bought a length of hose with some fittings.

grams · « **Reply #1 on:** 19 February, 2018, 01:51:51 pm »

I can't see any advantage in not replacing the whole hose.

(I'm intrigued by what bike you have that makes these are too short for. I fitted a similar set and ended up removing the short lever piece for both brakes and it came out just about the right length, but then I ride an S/52 frame)

Brucey · « **Reply #2 on:** 19 February, 2018, 02:14:44 pm »

If you have a half decent bleed kit then I suggest that you fit the hose empty and bleed it out afterwards.

cheers

Torslanda · « **Reply #3 on:** 19 February, 2018, 02:47:22 pm »

What he said.

Fit the caliper, then the lever, tape the hose in place and trim it to the correct length then remove it and fit the hardware on the hose - don't forget the rubber cover for the lever union - bleed in the approved manner.

Torslanda · « **Reply #4 on:** 19 February, 2018, 02:50:02 pm »

Are you fitting drops? If so ensure the lever bleed port is vertical or you risk leaving air in the master cylinder.

DAHIKT...

Brucey · « **Reply #5 on:** 19 February, 2018, 02:56:58 pm »

good point. The calipers can tend to trap air too if they are at the wrong angle and so can hose runs. In extremis it isn't a bad idea to mock up on the bike, get the hose lengths correct, then reposition everything to allow the best chances of a quick and thorough bleed. Often for a rear brake this necessitates that the whole bike is at a jaunty angle in the workstand, the handlebars are turned a bit and the MC is adjusted on the handlebar.

cheers

rafletcher · « **Reply #6 on:** 19 February, 2018, 03:36:50 pm »

Thanks chaps. The bike is a Genesis Equilibrium 56cm and the lever from Chain Reaction. No idea why it was too short. Anyway being impatient I went ahead and replaced the whole hose - I had a spare insert/olive from the hose kit I bought, and I recovered the insert and olive from the “easy connect” bit that came with the lever, as it hadn’t been tightened. All fitted now.

Luckily I have a good work stand that allows me to rotate the bike, and I bought extra oil when I bought a bleed kit, so should be ok. I may de- mount the rear calliper and let it hang down so the hose isn’t horizontal under the top tube while I’m doing it.

That’s the next job

Torslanda · « **Reply #7 on:** 19 February, 2018, 04:24:13 pm »

When bleeding brakes that are mounted within the rear triangle it's pretty much essential to remove the caliper and let it hang. It's the only way to get the bleed port below the hose connection.

Torslanda · « **Reply #8 on:** 19 February, 2018, 04:34:56 pm »

Quote from: grahamparks on 19 February, 2018, 01:51:51 pm

I can't see any advantage in not replacing the whole hose.

(I'm intrigued by what bike you have that makes these are too short for. I fitted a similar set and ended up removing the short lever piece for both brakes and it came out just about the right length, but then I ride an S/52 frame)

The split hose/union thing is for internally routed brakes. I had a similar issue before Xmas when fitting TRP (Hylex?) full hydro replacing TRP cable/hydro on a Pinnacle. This was an XL with a huge rise in the stem - customer has neck/back problems and rides VERY upright...

I buggered about with feeding the plain end of the hose up through the frame and after many BAD SWEARS^TM got the hose to appear in the right place. Only to discover - like the OP - that the hose was about a foot short. Had to obtain a genuine TRP replacement cos there was a banjo at the lever end but was a doddle to fit as the plain end of the hose fed down thru the frame and out the port under the BB.

rafletcher · « **Reply #9 on:** 19 February, 2018, 05:27:38 pm »

Hmm, well that could have gone better. Thought I'd done ok, but once returned to normal positions brake was terribly spongy. Enough for today though, I've left it with the calliper hanging down with the bike on the workstand. BUT I left the bleed nipple on the lever in - should I take it out? Logic tells me that even in a closed system the air should still rise - but nothing beats practical knowledge!

Edit: I had to go down anyway, so removed the lever bleed screw and put on the bleed reservoir. We’ll se what tomorrow brings.

Torslanda · « **Reply #10 on:** 19 February, 2018, 06:11:55 pm »

I wouldn't be at all surprised if you didn't have to repeat the bleeding process tomorrow.

As I said upthread, you need the nose of the lever pointed vertical, the blade almost horizontal...

rafletcher · « **Reply #11 on:** 19 February, 2018, 06:58:32 pm »

Well it isn’t at the mo, but all the hose run is more vertical than horizontal. So tomorrow I’ll rotate the bike nose down to try and get the air out of the reservoir.

These are drop bar levers btw.

rafletcher · « **Reply #12 on:** 20 February, 2018, 11:59:57 am »

Well I did bleed it again, but it's no better. It's fine, it works, but it has a slightly longer lever throw than the front (that came ready to use). I'll live with it and maybe see if the local bike mechanic can improve it at some point. Still I'm beck underway with all gears working too

Torslanda · « **Reply #13 on:** 20 February, 2018, 12:23:42 pm »

Out of curiosity I watched a youtube presentation on Ultegra levers last night. The guy was using the Shimano 'cup' screwed in to the top of the lever - the cup was vertical - and he was 'burping' the lever to expel the very last of the air before buttoning everything up.

jiberjaber · « **Reply #14 on:** 20 February, 2018, 01:09:26 pm »

Quote from: Torslanda on 20 February, 2018, 12:23:42 pm

Out of curiosity I watched a youtube presentation on Ultegra levers last night. The guy was using the Shimano 'cup' screwed in to the top of the lever - the cup was vertical - and he was 'burping' the lever to expel the very last of the air before buttoning everything up.

It sort of shows that in the Shimano instructions

http://si.shimano.com/pdfs/dm/DM-BR0008-08-ENG.pdf

Pgs 31 & 39

rafletcher · « **Reply #15 on:** 20 February, 2018, 02:34:47 pm »

Yep, the bleed kit I have from EBC has a syringe with adaptor that screws into the lever bleed port, rather than the Shimano cup. It also has a piston bleed block, a hose clamp for when you hammer the anti-crush spigot in, and a few other bits and pieces. And the instructions are basically are:

1) Inject c20ml in via calliper bleed port to raise level in lever syringe and (hopefully) expel the air.

2) Allow fluid to drain from calliper bleed port until lever syringe nearly empty.

3) With lever pulled in, open calliper bleed port in 1/2sec bursts to clear calliper. Pays to have help for this, or do as I did, employ a loop of zip-ties to keep lever pulled back.

4) "Flick" lever (pull in and allow to snap back) to "burp" the reservoir.

Rinse and repeat.

To be fair, allowing only a couple of ml out of the calliper meant the lever would go soft right back to the bars. The difference in mine may well be down to the greater length of hose to the back calliper, which will inevitably introduce a bit of flex.

Feanor · « **Reply #16 on:** 20 February, 2018, 02:45:15 pm »

I've yet to break into the hydraulics on Mrs F's road bike.

All this gravity-based bleeding sound a bit hit-and-miss to me.

Is no-one making a pressurised bleeding system for bikes ( like the Gunson Eezibleed system wot I did use with my old rust-bucket cars back in the day )?

It always gave much better results that the 2-man method with one person slowly pumping the brake pedal, whist the other grazed his knuckles on all 3 hands alternately opening and closing the bleed ports on the caliper whilst holding the stupid rubber hose onto the nipple and holding the jam-jar in the right place.

Brucey · « **Reply #17 on:** 20 February, 2018, 03:15:59 pm »

the method that works best, quickest, is to push fluid from the caliper to the MC. Pushing fluid the other way can allow bubbles to remain in the same place in the hoses, and certainly does not eliminate them in a positive fashion.

cheers

rafletcher · « **Reply #18 on:** 20 February, 2018, 03:18:20 pm »

Well Shimano do a “professional” kit it seems

https://www.rosebikes.com/article/shimano-tl-bt03-professional-bleed-kit/aid:804633

The only difference over the £15 kit I used is the drain is a vented bottle, not a plastic bag zip-tied to a bit of tube, plus the fancy device for (I assume) being the third hand on the lever.

But having observed the flow of oil down the vent tube when letting the reverse flow through, gravity looks to do a pretty good job. The oil’s not very viscous and air bubble easily move, particularly with a bit of percussive persuasion.

rafletcher · « **Reply #19 on:** 20 February, 2018, 03:20:28 pm »

Quote from: Brucey on 20 February, 2018, 03:15:59 pm

the method that works best, quickest, is to push fluid from the caliper to the MC. Pushing fluid the other way can allow bubbles to remain in the same place in the hoses, and certainly does not eliminate them in a positive fashion.

cheers

Yep, a good push on the syringe into the calliper, a slow drain back, then repeat seems best.

jiberjaber · « **Reply #20 on:** 20 February, 2018, 03:24:58 pm »

I have the BT03 bleed kit (small version, so no clamp or bottle that's in the pro version). Not used it yet but getting close on my rear brake. Looking forward to a better experience than bleeding hy-rd calipers!

rafletcher · « **Reply #21 on:** 20 February, 2018, 03:28:14 pm »

Does it include a block for replacing the pads when bleeding? That’s an essential part IMO as, as has been mentioned, the rear calliper is best de-mounted for bleeding.

jiberjaber · « **Reply #22 on:** 20 February, 2018, 03:57:52 pm »

Quote from: rafletcher on 20 February, 2018, 03:28:14 pm

Does it include a block for replacing the pads when bleeding? That’s an essential part IMO as, as has been mentioned, the rear calliper is best de-mounted for bleeding.

No I didn't see one in the contents list so I bought one just in case

https://www.bike24.com/1.php?content=8;product=27064;menu=1000,2,15,117;page=61

Spacer:
https://www.bike24.com/p2119074.html

I'm assuming it will fit my RS805 brakes when I get round to it.

rafletcher · « **Reply #23 on:** 20 February, 2018, 04:47:19 pm »

That’s the jobbie

my kit had both the large yellow one that replaces the pads, and the thinner one that you can push between them. I’m messy so chose to remove the pads.