Honda-SOHC

SOHC.co.uk Forums => CB500/550 => Topic started by: wolfheze on April 16, 2018, 07:17:57 PM

Title: Bleeding brake.
Post by: wolfheze on April 16, 2018, 07:17:57 PM: Can anyone enlighten me on how to bleed the brakes? Have fitted a master cylinder rebuild kit but can't get much fluid out of the bleed nipple. The line and caliper haven't been drained so the problem is at the master cylinder. Any tips?
Title: Re: Bleeding brake.
Post by: Trigger on April 16, 2018, 09:15:38 PM: Did you clean the master cylinder out and check that both holes are clear ;)
Title: Re: Bleeding brake.
Post by: wolfheze on April 17, 2018, 04:38:38 AM: Yes, i checked the holes visually but with hindsight i should have pushed something through the small one to make sure. The inside of the master cylinder was already very clean but I did wash it through. On doing some research it seems as though it can be quite tricky, someone suggested priming the master cylinder with the hose disconnected, makes sense but I'm a bit reluctant to try it because of the risk of spillage.
Title: Re: Bleeding brake.
Post by: Bryanj on April 17, 2018, 07:27:56 AM: I have documented before on here on how to get the master to pump and it is with pipe disconnected, only way if its being stuborn
Title: Re: Bleeding brake.
Post by: Seabeowner on April 17, 2018, 09:00:14 AM: I found that lots of small strokes of the lever got it started. Just pulling the lever back maybe 1" at the end a few times, then some even smaller strokes and then pausing and repeating.
Title: Re: Bleeding brake.
Post by: wolfheze on April 17, 2018, 09:13:37 AM: Quote from: Bryanj on April 17, 2018, 07:27:56 AM
I have documented before on here on how to get the master to pump and it is with pipe disconnected, only way if its being stuborn
Is that the squeeze lever then finger over the end and release lever method?
Title: Re: Bleeding brake.
Post by: Spitfire on April 17, 2018, 11:50:53 AM: As someone else has said I pump the front brake lever in small strokes and then one big one until no more bubbles appear, I also make sure by moving the bars to one side that the master cylinder is as high as possible.

Cheers

Dennis
Title: Re: Bleeding brake.
Post by: Johnwebley on April 17, 2018, 12:54:19 PM: does your caliper have fluid in it ?

you could connect it all together,then press the piston in,and force the fluid up the pipes into the master cylinder ,
Title: Re: Bleeding brake.
Post by: wolfheze on April 17, 2018, 03:43:16 PM: Yes the caliper still has fluid in it. Have just got back from the garage after spending two hours pumping that bloody lever.! Tried priming the master cylinder and that didn't work either. I'll take it back into work tomorrow and try to strip it down again to make sure I've assembled it properly. If I muller it getting it apart I'll buy a new master cylinder, hope I dont have to because I don't really want pattern parts on the bike.
Title: Re: Bleeding brake.
Post by: Johnwebley on April 17, 2018, 03:54:56 PM: I am using a D Silver master cylinder (GL1100 for twin discs) ,It looks exactly the same and works perfectly,
I doubt any casual observer would tell any difference.

and a bargain at approx £30
Title: Re: Bleeding brake.
Post by: wolfheze on April 17, 2018, 04:08:25 PM: Are they still ok to use with a single disc?
Title: Re: Bleeding brake.
Post by: hairygit on April 17, 2018, 04:10:24 PM: Quote from: wolfheze on April 17, 2018, 04:08:25 PM
Are they still ok to use with a single disc?
He does the version for single disc as well at the same bargain price.

Sent from my X6pro using Tapatalk
Title: Re: Bleeding brake.
Post by: wolfheze on April 17, 2018, 04:17:41 PM: Out of stock. Would the Honda brake lever fit? Would like to use it if possible as it's still got the rubber end on it.
Title: Re: Bleeding brake.
Post by: Bryanj on April 17, 2018, 04:36:05 PM: Yes the method you found has never failed for me
Title: Re: Bleeding brake.
Post by: wolfheze on April 17, 2018, 05:32:37 PM: There didn't seem to be much suction on my finger when the lever was released so I'm thinking I've managed to assemble it wrong :-[
Title: Re: Bleeding brake.
Post by: wolfheze on April 18, 2018, 08:57:11 AM: [attachimg=1][attachimg=2]
Stripped down the cylinder and everything seems ok. A couple of petals seem to be slightly more bent upwards but apart from that looks perfect to me
Title: Re: Bleeding brake.
Post by: hairygit on April 18, 2018, 09:11:39 AM: There isn't supposed to be any suction, the fluid is returned to the master cylinder by the seal in the caliper pulling back into it's correct position after being distorted by the fluid entering it under pressure from the master cylinder. There should be pressure at the master cylinder when you pull the lever with your finger over the end of it, did you get pressure?
Title: Re: Bleeding brake.
Post by: wolfheze on April 18, 2018, 09:17:27 AM: I don't think so
Title: Re: Bleeding brake.
Post by: wolfheze on April 18, 2018, 12:06:23 PM: Reassembled and ready for another go. For some reason it seems to be pushing in more smoothly but at the same time there's more resistance.
Title: Re: Bleeding brake.
Post by: wolfheze on April 18, 2018, 07:45:20 PM: Done! Really easy this time. Got a much much better feeling lever now. Was really wooden feeling before and the brake actually feels like it would stop you! Suspect there was air in it before.
Title: Re: Bleeding brake.
Post by: jon stead on April 18, 2018, 08:48:36 PM: Quote from: wolfheze on April 18, 2018, 07:45:20 PM
Done! Really easy this time. Got a much much better feeling lever now. Was really wooden feeling before and the brake actually feels like it would stop you! Suspect there was air in it before.
Good job. Always good to hear of success.
Title: Re: Bleeding brake.
Post by: wolfheze on April 19, 2018, 06:02:23 AM: Thanks for the advice, still trying to fathom out why it wouldn't work the first time.
Title: Re: Bleeding brake.
Post by: Bryanj on April 19, 2018, 07:27:42 AM: Sod's sixth law mate