Honda-SOHC
SOHC.co.uk Forums => CB750 => Topic started by: RGP750 on March 02, 2017, 06:58:06 PM
-
Bike is almost finished and i have filled the master cylinder and have a problem.
The body was cleaned and a new plunger/seal kit fitted.
The brake fluid won't pump down the pipes.
I have the nipple removed and left the cylinder filled last night with the lever pulled in (i assume this
will leave the access out open).
No fluid has left the cylinder,pumping the lever doesn't make it move either.
I took the lever off and the plunger mover freely by pushing with a brass rod.
Any ideas welcome please.
Rich
-
Prime the master cylinder ;)
-
Hi Rich
I had a similar problems a few years ago when I built my K2 - it turned out to be one off the tiny holes blocked. Cleared it with a 1mm drill bit and bleed straight away
Phil
-
I have Trigg.
I'll take a look at that Phil Ta.
-
Me again
Taken master cylinder off, washed out and yes Phil hole looks blocked, i used a
jewelers eye glass and the hole is minute.
One strand of copper harness wire won't clear it.
Is it ok to open the hole up? I probably have a .5mm drill at work
but that is larger than what is there.
Rich
-
Is that the one Trig stripped down for you 2 years ago Rich?. If it is, it's taken you long enough to realise the hole is blocked ;D ;D Mind you, at least you haven't lost it which is a major result!!! Xxx
-
Re building is a learning curve for the first major re build i'm sure you know Julie.
Did Trig leave it blocked to see if i noticed then ????? ;) ;D ;D ;D
-
Hehe, yes, I'm sure I saw him plug the hole just in case you lost something down it ;D ;D I wouldn't know where to start with a master cylinder rebuild Rich, luckily I have never had to do more than top them up with oil, luck I suppose.
-
Re building is a learning curve for the first major re build i'm sure you know Julie.
Did Trig leave it blocked to see if i noticed then ????? ;) ;D ;D ;D
I can remember advising you when I stripped both the master cylinders to check the holes ;D
-
I used a 1mm and everything has been fine with braking after about 800 miles. Like you said Rich, I couldn't shift the crud without drilling it out - I think I used a small adjustable collet tap wrench (with tin foil wrapped around the drill bit to get the grip) then turned it by hand. But using a small variable speed drill should be ok in my opinion
Sent from my MotoG3 using Tapatalk
-
I use two strands of copper multistrand flex twisted together
-
Thanks all.
I tried the copper wire trick, no luck, pulled a bristle out of a wire brush, still no luck .
I found a .6mm drill and i have a pin chuck so going to strip out the new plunger etc, When i can get the
blooming circlip out.
I have bought a new repair kit. Drill out the hole and have another go.
Report back later.
Cheers
-
I'm just having the same problem. Fitted the rebuild kit last night.
Can someone tell me what the two holes in the master cylinder reservoir do please. I can see the piston move through one....but not the other.
Sent from my iPad using Tapatalk
-
The hole nearest the lever is quite large but the one nearest the banjo is VERY small you will need a magnifying glass to see it well.
This hole seems prone to blocking if it is an old master cylinder and corroded.
I propose to drill mine out this weekend.
-
The hole nearest the lever is quite large but the one nearest the banjo is VERY small you will need a magnifying glass to see it well.
This hole seems prone to blocking if it is an old master cylinder and corroded.
I propose to drill mine out this weekend.
Cheers....I boiled mine when I disassembled it....so hopefully it will poke thru?
Sent from my iPad using Tapatalk
-
Can someone tell me what the two holes in the master cylinder reservoir do please.
The big hole is to let fluid into the cylinder to be pumped, the small hole is to allow a small amount of fluid back into the res' when you release the lever so the brake piston can back off a little, if its blocked you will have drag. Commonly known as a "spooge hole"
-
Cylinder stripped. "spoogle" hole drilled out ,new Plunger etc fitted.
and bled.
Works a treat.
Thanks again to this forum and it's members.
I have the bike booked in at Ardingly show 2 April.
Never put a bike into a show before .
Anyone on here going?
Cheers again Rich
-
Cylinder stripped. "spoogle" hole drilled out ,new Plunger etc fitted.
and bled.
Works a treat.
Thanks again to this forum and it's members.
I have the bike booked in at Ardingly show 2 April.
Never put a bike into a show before .
Anyone on here going?
Cheers again Rich
I have scrutinised your entry form as head judge, and I look forwards to see the completed bike ;)
-
I will
Put up photos as well Trigg ,i welcome your scrutiny and comments ;)
-
I will
Put up photos as well Trigg ,i welcome your scrutiny and comments ;)
I will be keeping my eye out for incorrect fitted springs ;D ;D ;D
-
If that's all you find i will be happy :D :D
(and you won't find that) ;)
-
Can someone tell me what the two holes in the master cylinder reservoir do please.
The big hole is to let fluid into the cylinder to be pumped, the small hole is to allow a small amount of fluid back into the res' when you release the lever so the brake piston can back off a little, if its blocked you will have drag. Commonly known as a "spooge hole"
Thank you
Sent from my iPad using Tapatalk