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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Supershooter on March 09, 2019, 06:37:13 PM

Title: I知 installing a kit into my front master cylinder, is this too much pitting?
Post by: Supershooter on March 09, 2019, 06:37:13 PM
I知 installing a kit into my front master cylinder, is this too much pitting? Or is it salvageable?
Title: I知 installing a kit into my front master cylinder, is this too much pitting?
Post by: Martin on March 09, 2019, 09:50:10 PM
Looks to deep to me to hone. Either pickup a second hand one or get a rebore and sleeve job. However Gryph has tried this in the US and was not happy with the results.  He might let you know where not to go. I'm fortunate in that we have local guy that does sleeving and guarantees all his work. Last time I enquired it was $200.00 Au and a rebuild  rubbers kit once done is $10.00 Au. Apparently only two place in OZ do it. He does do overseas work but cost might prohibitive.
Regards Martin.

* Boots and cups supply[1].jpg (55.42 kB . 768x576 - viewed 571 times)
Title: I知 installing a kit into my front master cylinder, is this too much pitting?
Post by: The Mighty Gryphon on March 10, 2019, 03:16:38 PM
Sleeving is a waste of money.  They destroyed the plastic fitting with the hose barb for the hose to the reservoir.  The sleeved master cylinder never worked, even with an $85 rebuild kit with new piston.  Altogether a total waste of $192.

Blow 11 bucks and a couple hours adapting a Chicom master cylinder to your bike.  I just changed one on Cheetos, and it took me 2 1/2 hours start to finish including a trip to the auto parts store for 5/16" hose.

https://www.ebay.com/itm/Motorcycle-Rear-Foot-Brake-Master-Cylinder-Reservoir-ATV-Dirt-Bike-Sportbike/311868784114?epid=1195616246&hash=item489cd3fdf2:g:SlYAAOSwnOtbF8XX&frcectupt=true

The process is in a thread here at Motobrick.  The one I did in the thread has over three years and about 30,000 miles on it.
Title: I知 installing a kit into my front master cylinder, is this too much pitting?
Post by: Martin on March 10, 2019, 04:44:26 PM
Gryph he said front master cylinder. I also talked to a guy who had a sleeving job done by the Guy in South Australia on a Quacker and he was happy. Glen the local guy does not like doing BMW rears due to the fact the plastic is prone to breaking. However if it breaks he machines up a new one in brass complete with an "O" ring seal.  He also makes his own  imperial pistons and that makes replacement cups cheap. I haven't heard of him doing a shoddy job yet. Surely in the great land of the US there is a competent mob doing stainless sleeving, and there must be more than one even we have two.
Regards Martin.
Title: Re: Re: What Did You Did To Your Motobrick Today ?
Post by: Supershooter on March 10, 2019, 10:01:26 PM
I was excited for an aftermarket /shop solution, but I'm working on a front master cylinder not a rear. Thanks for the link, any help or thoughts on a front?

Supershooter
Title: Re: I知 installing a kit into my front master cylinder, is this too much pitting?
Post by: Supershooter on March 11, 2019, 09:12:25 PM
I've got 80 grit is that too aggressive? I can probably fine something finer. Thoughts?
Supershooter
Title: Re: I知 installing a kit into my front master cylinder, is this too much pitting?
Post by: BryanD on March 11, 2019, 10:01:50 PM

If I'm interpreting the photo of that rust gully in OP's master correctly, it would take about 100 years with 1000 grit to get that baby honed. 
Title: Re: I知 installing a kit into my front master cylinder, is this too much pitting?
Post by: Supershooter on March 13, 2019, 07:45:56 AM

i recall it being 1000

Johnny, Did you mean 100?

Supershooter
Title: Re: I知 installing a kit into my front master cylinder, is this too much pitting?
Post by: The Mighty Gryphon on March 13, 2019, 09:58:12 AM
1000 grit wet or dry.  You are polishing the bore, not plowing to plant corn.
Title: Re: I知 installing a kit into my front master cylinder, is this too much pitting?
Post by: Laitch on March 13, 2019, 10:08:32 AM
Consider using a 13mm bore brush to remove the rough stuff before sanding.
Title: Re: I知 installing a kit into my front master cylinder, is this too much pitting?
Post by: Supershooter on March 13, 2019, 10:15:55 AM
I used a bore brush and brake clean from one of my gun cleaning supplies to get it this clean.
Supershooter
Title: Re: I知 installing a kit into my front master cylinder, is this too much pitting?
Post by: johnny on March 25, 2019, 11:15:15 AM
greetings...

what was used here was 1220 gritt...

(https://i236.photobucket.com/albums/ff192/owrstrich/3e181216.jpg)

j o
Title: Re: I知 installing a kit into my front master cylinder, is this too much pitting?
Post by: Supershooter on March 25, 2019, 10:47:03 PM
I used 1000 grit wet dry sandpaper, I'd cut the sandpaper into small pieces then wrap them around and ink pen and sand until the paper was shot. After 3.5 hour of sanding I quit and reassembled the master cylinder. It seems to be holding. Time will tell.

Supershooter
Title: Re: I知 installing a kit into my front master cylinder, is this too much pitting?
Post by: Laitch on March 26, 2019, 08:53:14 AM
Quote from: Supershooter on March 25, 2019, 10:47:03 PM
After 3.5 hour of sanding . . .
:clap: