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1Back to top Go down    Rear Master Cylinder Repair on Tue Sep 25, 2012 3:04 am

rosskko

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Quick question = hopefully quick answer.

My rear cylinder is leaking beneath the plastic plug at the to of the cylinder, where the hose connects from the reservoir.
Can I fixi it?

I think it's the problem of not getting brake pressure

rossco


__________________________________________________
1986 K100RT VIN 0093801K100RT with summer fairing for a northern visitor

Basic/2 6308802K100CJ  05/1988

K1100RS 0194321
    

2Back to top Go down    Re: Rear Master Cylinder Repair on Tue Sep 25, 2012 3:52 am

K75cster

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Fix it? Yes You Can (allways wanted to say that) that's the line running from the resivoir to the master isn't it? its just a utility line and goes from the spigot at the resivoir to the spigot at the master, if there is enough there you can snip off the broken bit and reapply the line


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Keith - 1987 K75c with r100rt replica fairing and half of a 1984 K100rt 1992 K1100LT a blue one

The Clever are adept at extricating themselves from situations that the wise would have avoided from the outset - QUOTE from david Hillel in Out of the Earth.
    

3Back to top Go down    Re: Rear Master Cylinder Repair on Tue Sep 25, 2012 4:01 am

rosskko

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Thanks Keith, but the line is new. The problem is the actual black plastic part on top of the cylinder. It is leaking from between the plastic and the metal.
Does this screw on? Mine seems to turn a bit.
This rear brake is giving me the poos.
It is the last thing I need to fix to get the bike back on the road.


__________________________________________________
1986 K100RT VIN 0093801K100RT with summer fairing for a northern visitor

Basic/2 6308802K100CJ  05/1988

K1100RS 0194321
    

4Back to top Go down    Re: Rear Master Cylinder Repair on Tue Sep 25, 2012 4:12 am

RicK G

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rossco wrote:Thanks Keith, but the line is new. The problem is the actual black plastic part on top of the cylinder. It is leaking from between the plastic and the metal.
Does this screw on? Mine seems to turn a bit.
This rear brake is giving me the poos.
It is the last thing I need to fix to get the bike back on the road.

No it does not screw on. Its a one use only as in when you get it out its shagged, it pushes in and will not come back out without a fight which it loses every time.
I had a master cylinder resleeved a while ago and a new one was used so you can get the part.
Some of the resleeving mobs may be able to supply one, there is a Mazda one that fits the hole but has the wrong hose fitting so be careful what they try to sell you.
That will not be where the brake problem is. Check that the piston is not stuck in the bottom of the bore and that you are just working against the spring or that the little allen head screw isnt jaming the piston and causing the same problem.


__________________________________________________
"Every normal man must be tempted, at times, to spit upon his hands, hoist the black flag, and begin slitting throats."  from Mencken's 1919 Prejudices

Bikes 1993 K1100 LT, 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 for now
    

5Back to top Go down    Re: Rear Master Cylinder Repair on Tue Sep 25, 2012 4:50 am

K75cster

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Ok i will go out and put me footpeg hanger back on then, i have an idea, as in using teflon tape to bind the join? Its supposed to be a interference fit isn't it? maybe binding it might work, thts if we are talking about the spigot for the resevoir being the culprit, not another piece of the master


__________________________________________________
Keith - 1987 K75c with r100rt replica fairing and half of a 1984 K100rt 1992 K1100LT a blue one

The Clever are adept at extricating themselves from situations that the wise would have avoided from the outset - QUOTE from david Hillel in Out of the Earth.
    

6Back to top Go down    Re: Rear Master Cylinder Repair on Tue Sep 25, 2012 5:45 am

rosskko

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Day off tomorrow. Going to bleed, clean, scrub and get that damn thing working. All I want is five minutes of the brake doing its thing so I can get a blue slip.
I took a gamble and got the repair kit instead of the whole brake assembly. Looks like the gamble did not pay off.
As soon as I get a blue slip I can wait the week to get a new master cylinder from the uk.


__________________________________________________
1986 K100RT VIN 0093801K100RT with summer fairing for a northern visitor

Basic/2 6308802K100CJ  05/1988

K1100RS 0194321
    

7Back to top Go down    Re: Rear Master Cylinder Repair on Sat Dec 09, 2017 4:04 am

KiwiK100

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I have the same leaking rear master cylinder that Rosskko had. What was the fix in the end? I have the same problem and need to sort it. Did he end up getting a new MC from the UK? I have already put a recon kit into the MC, so have already thrown cash at it. Would be a shit to then buy a whole new MC. This fitting is not under pressure so can't see why a DIY fix wouldn't work, it's just a matter of working out what to use. Anyone else fixed this without buying a new MC?



Last edited by KiwiK100 on Sun Dec 10, 2017 4:46 am; edited 1 time in total


__________________________________________________
Current rides:
2002 K1200RS. Owned from new. Pacific Blue, Ohlins, Speiglers, Fiamms, HID. 167,000km
1991 K1. Schwartz metallic black, 18 month frame off restoration. 74,000km
1987 K100RS Style. Black, Ohlins, Race Tech springs, Braided lines. Fully restored. 53,000 miles. 
The family history:
1951 AJS 500 single - my Dads ride
1953 Triumph Terrier - my Mum's ride
1916 Triumph Type H, Battle of the Somme, France WW1 - my Grand dads ride
    

8Back to top Go down    Re: Rear Master Cylinder Repair on Sat Dec 09, 2017 6:07 am

MartinW

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See here http://www.motobrick.com/index.php/topic,9364.msg90596.html#msg90596  I've been running a Chinese master cylinder since March and I'm very happy with it easy installation, depending on your model you may have to change the hose. A mate of a mate came round today and I gave him my spare one. At a cost of under $13.00 Au not even worth putting a kit in.
Regards Martin.



Last edited by MartinW on Sat Dec 09, 2017 6:20 am; edited 1 time in total (Reason for editing : Added Photo)

    

9Back to top Go down    Re: Rear Master Cylinder Repair on Sat Dec 09, 2017 6:33 am

RicK G

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I bought one of these recently but haven't played with it yet. Holes are almost right and a small round file would do the job.
https://www.ebay.com.au/itm/Motorcycle-Accessories-Brake-Master-Cylinder-Caliper-Pump-Rear/232440270907?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649


__________________________________________________
"Every normal man must be tempted, at times, to spit upon his hands, hoist the black flag, and begin slitting throats."  from Mencken's 1919 Prejudices

Bikes 1993 K1100 LT, 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 for now
    

10Back to top Go down    Re: Rear Master Cylinder Repair on Sat Dec 09, 2017 7:32 am

Dai

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Won't fit. As you say, the holes are almost right but the mounting bosses push the master cylinder about 2mm to one side compared to the brake pedal pivot. I spent hours cutting and filing to get the damn thing lined up, only to find that the pushrod operating angle was too steep. I consoled myself with the thought that at least I'd got a spare rear hydraulic reservoir.

If you do have a go Rick, make sure you have a good milenicut or dreadnought file - that ally clogs a second-cut file in less than two seconds flat. I ended up cutting the holes using careful side pressure on a drill bit in my pillar drill. I got very focused on making the master cylinder line up with the brake pedal, so a second pair of eyes could come up with a much better method.


__________________________________________________
'83 K100 upgraded to K100RS spec
Others...
'78 Moto Guzzi 850-T3, '79 Moto Guzzi 850-T3 California,'93 Moto Guzzi 1100ie California,
'03 Suzuki Blandit GSF600SK3 (NFS any more because wifey has claimed it)
    

11Back to top Go down    Re: Rear Master Cylinder Repair on Sat Dec 09, 2017 8:05 am

Point-Seven-five

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Page 2 look for posts by the Mighty Gryphon.  They document my very successful retrofit of a cheap Chinese master cylinder that as of now has nearly 6.000 miles on it and is still working flawlessly.

http://www.motobrick.com/index.php/topic,9364.25.html


__________________________________________________
Present:
1994 K75RT
1994 K75S
1992 K100RS

Past:
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

12Back to top Go down    Re: Rear Master Cylinder Repair on Sat Dec 09, 2017 7:52 pm

RicK G

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@Dai wrote:Won't fit. As you say, the holes are almost right but the mounting bosses push the master cylinder about 2mm to one side compared to the brake pedal pivot. I spent hours cutting and filing to get the damn thing lined up, only to find that the pushrod operating angle was too steep. I consoled myself with the thought that at least I'd got a spare rear hydraulic reservoir.

If you do have a go Rick, make sure you have a good milenicut or dreadnought file - that ally clogs a second-cut file in less than two seconds flat. I ended up cutting the holes using careful side pressure on a drill bit in my pillar drill. I got very focused on making the master cylinder line up with the brake pedal, so a second pair of eyes could come up with a much better method.
It'll be a while yet, I have to finish refitting my Caravan and painting the house and................................^*(#@^%$


__________________________________________________
"Every normal man must be tempted, at times, to spit upon his hands, hoist the black flag, and begin slitting throats."  from Mencken's 1919 Prejudices

Bikes 1993 K1100 LT, 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 for now
    

13Back to top Go down    Re: Rear Master Cylinder Repair on Sun Dec 10, 2017 4:57 am

KiwiK100

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The Clever are adept at extricating themselves from situations that the wise would have avoided from the outset - QUOTE from david Hillel in Out of the Earth.

This is a quote from 75cster's signature. Clearly, had I engaged my brain before my fingers I would have realised that Rosskko passed some time back, and in referencing him in an enquiry for assistance, I have dug a huge hole for myself that I'd like to crawl into and die. I am neither clever enough to extricate myself from this, and obviously not wise enough to have avoided the situation in the first place. While I joined the forum after Rosskko's passing, I was aware of this and should have known better.
My sincere apologies to all that knew him personally, and to those that I have offended.


__________________________________________________
Current rides:
2002 K1200RS. Owned from new. Pacific Blue, Ohlins, Speiglers, Fiamms, HID. 167,000km
1991 K1. Schwartz metallic black, 18 month frame off restoration. 74,000km
1987 K100RS Style. Black, Ohlins, Race Tech springs, Braided lines. Fully restored. 53,000 miles. 
The family history:
1951 AJS 500 single - my Dads ride
1953 Triumph Terrier - my Mum's ride
1916 Triumph Type H, Battle of the Somme, France WW1 - my Grand dads ride
    

14Back to top Go down    Re: Rear Master Cylinder Repair on Sun Dec 10, 2017 5:26 am

charlie99

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mate if you can get all the brake fluid out of the plug seal area ...perhaps with a bit of modelling clay around the lower part of the plug ...master cylinder body  you could form a loose former  so that something like jb weld could be used to seal it up ?  even that permatex liquid metal stuff ..might be an option ...but as I said hard to get oily substances out of tricky places for the adhesion to fix properly ..

rossco had devils own issues with his rear master cylinders

I remember one time he lost the pump action ,,,  finally found some time later to be the equalizer hole being blocked ....the real issue was actually finding it ..way down inside the bore   with no reference pictures available ...well, that we knew of at the time .



just an idea ..I guess nothing to loose

good luck


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cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
    

15Back to top Go down    Re: Rear Master Cylinder Repair on Sun Dec 10, 2017 11:45 am

Point-Seven-five

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Has anyone looked at the link I posted?  I really can't understand all the trouble this is giving people.  My retrofit cost less than $20 total, and I did all the work on a Sunday morning in 2-3 hours.  It's a piece of cake if you start with the right master cylinder, and it's linked in the posted thread.  Mounting holes were perfectly spaced so it was a stright bolt up, and the plunger lined up perfectly with the pedal.

Most of the time on my retrofit was spent modifying the plunger rod to work with the pedal.  Measured the required length from the old one, cut off the new one, and counterbored the end of the new rod to create a dimple for the ball on the pedal to ride in.  It's all there including photos.


__________________________________________________
Present:
1994 K75RT
1994 K75S
1992 K100RS

Past:
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

16Back to top Go down    Re: Rear Master Cylinder Repair on Sun Dec 10, 2017 1:55 pm

Woodie

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I can affirm what Point-Seven-five is saying.  It was a much easier retrofit than I thought it might be and I think it took me longer to bleed the brakes than it did to cut the plunger rod and install everything.  I've got at least 4000 miles on mine and it has performed really well, to the point where I think I might need ABS.  Definitely not the case with the previous OEM (but very worn out) cylinder.


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1985 K100RT
52667
    

17Back to top Go down    Re: Rear Master Cylinder Repair on Sun Dec 10, 2017 3:43 pm

MartinW

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+1 easy cheap mod straight forward mod although I did it slightly differently. I pulled apart the master cylinder and checked and there is nothing wrong with the quality. I have now ordered and received four two for me two for a mate. Last week a mate of a mate came over and I gave him my spare. I have ordered another one a spare as at a cost of under $15.00 Au I wouldn't even bother putting a kit in it. Replacement cups locally can be had for $10.00 a better replacement boot is $4.00.
Regards Martin.

    

18Back to top Go down    Re: Rear Master Cylinder Repair on Mon Dec 11, 2017 4:38 am

KiwiK100

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I happen have the JB Weld handy, so after a thorough bath with isopropyl alcohol I filled the gap between the aluminium body and the black plastic fitting with said JB. There was a gap, about 0.5mm which seems ideal to fill, so once cured and the MC repainted, I will reinstall and see what cooks. I'm confident it will work as the brake fluid is gravity fed and not under any pressure. Time will tell as it usually does...


__________________________________________________
Current rides:
2002 K1200RS. Owned from new. Pacific Blue, Ohlins, Speiglers, Fiamms, HID. 167,000km
1991 K1. Schwartz metallic black, 18 month frame off restoration. 74,000km
1987 K100RS Style. Black, Ohlins, Race Tech springs, Braided lines. Fully restored. 53,000 miles. 
The family history:
1951 AJS 500 single - my Dads ride
1953 Triumph Terrier - my Mum's ride
1916 Triumph Type H, Battle of the Somme, France WW1 - my Grand dads ride
    

19Back to top Go down    Re: Rear Master Cylinder Repair on Mon Dec 11, 2017 7:28 am

Dai

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Two stones to kill the same bird. I wanted to retain the OEM look.

And no comments about the rest of the bike, gentlemen, purleeze. Razz


__________________________________________________
'83 K100 upgraded to K100RS spec
Others...
'78 Moto Guzzi 850-T3, '79 Moto Guzzi 850-T3 California,'93 Moto Guzzi 1100ie California,
'03 Suzuki Blandit GSF600SK3 (NFS any more because wifey has claimed it)
    

20Back to top Go down    Re: Rear Master Cylinder Repair on Mon Dec 11, 2017 7:54 am

Chocolate

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@Point-Seven-five wrote:Has anyone looked at the link I posted?  I really can't understand all the trouble this is giving people.  My retrofit cost less than $20 total, and I did all the work on a Sunday morning in 2-3 hours.  …

Hello Point-Seven-five, would be nice if you could post the link directly here, where to buy. As you are describing it fits plug and play right !?
Thanks for your help

Cheers


__________________________________________________
Only a few activities make me experience my senses in a way motorcycle riding does, it is like swimming in the nude in a river.
K75 BA/1992 ABS, K75 BA/1991 noABS, Ducati, Mobylette M1/1973
    

21Back to top Go down    Re: Rear Master Cylinder Repair on Mon Dec 11, 2017 11:04 am

Laitch

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@Chocolate wrote:Hello Point-Seven-five, would be nice if you could post the link directly here, where to buy.

Here is the original post containing links to the alternative master cylinder. .75 took it from there and did the slight modifications for fitment that he has described.


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1995 K75T 68,000 miles
    

22Back to top Go down    Re: Rear Master Cylinder Repair on Mon Dec 11, 2017 11:38 am

Chocolate

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Thanks Laitch, got it ;-)

Cheers


__________________________________________________
Only a few activities make me experience my senses in a way motorcycle riding does, it is like swimming in the nude in a river.
K75 BA/1992 ABS, K75 BA/1991 noABS, Ducati, Mobylette M1/1973
    

23Back to top Go down    Re: Rear Master Cylinder Repair on Mon Dec 11, 2017 11:52 am

Point-Seven-five

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__________________________________________________
Present:
1994 K75RT
1994 K75S
1992 K100RS

Past:
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

24Back to top Go down    Re: Rear Master Cylinder Repair on Mon Dec 11, 2017 2:24 pm

MartinW

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I've just ordered another one from Aliexpress $10.21 US  Free shipping. This will be my fifth from the same vendor.
https://www.aliexpress.com/item/Motorcycle-Rear-Foot-Hydraulic-Brake-Pump-For-Suzuki-Kawasaki-Honda-Yamaha-Refit-Rear-Brake-Master-Cylinder/32789801624.html?
Regards Martin.

    

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