84 RZ master cylinder

General forum on frames, brakes, suspension, wheels and tires

Moderator: rztom

Post Reply
Message
Author
75RD350rider
Posts: 601
Joined: Thu Jun 19, 2014 9:52 pm

84 RZ master cylinder

#1 Post by 75RD350rider » Wed Nov 04, 2015 9:15 pm

I am in the process of beginning the brake refurb on my RZ . The master cylinder was pretty nasty and the brakes are dragging. The calipers will come off soon to be cleaned well to include bead blasting the bodies and painting. Upon removal I noted two small holes side by side inside the master cylinder as depicted. The one on the right under the #2 is open and you can see the mechanism moving when you squeeze the brake lever. The other appears to not go anywhere? Or is it corroded closed or blocked?

Image

Thanks in advance to any and all who reply.
I love the smell of Blue Marble in the morning!
Tim Steele in Front Royal, VA

User avatar
T.RexRacing
Posts: 1318
Joined: Fri Nov 01, 2013 8:34 pm
Location: back in the hills

Re: 84 RZ master cylinder

#2 Post by T.RexRacing » Wed Nov 04, 2015 10:33 pm

Clogged. A small hole but it's there. If it were mine I'd disassemble and rebuild. The rebuild kit #4K0-W0041-00-00 isn't cheap (almost $50) but it's the brakes. Unfortunately the rubber parts aren't available separately. You can try disassemble clean and reassemble but be prepared to do it again if it leaks. I'd take it apart and use brake cleaner and compressed air to open it up.

BTW caliper rebuilds are expensive too. May as well buy all the parts at once. I use boats.net. Brake lines are old too. Cheaper to replace with braided stainless.
There is only one difference between a madman and me. The madman thinks he is sane. I know I am mad.
Salvador Dali

75RD350rider
Posts: 601
Joined: Thu Jun 19, 2014 9:52 pm

Re: 84 RZ master cylinder

#3 Post by 75RD350rider » Wed Nov 04, 2015 10:38 pm

Thanks so much. I already have stainless lines. I may just buy a new master cylinder. I have had abysmal luck in the past attempting rebuilds. Is there a similar arrangement on the rear?
I love the smell of Blue Marble in the morning!
Tim Steele in Front Royal, VA

silverstrom
Moderator
Moderator
Posts: 7030
Joined: Wed Mar 24, 2010 2:20 am

Re: 84 RZ master cylinder

#4 Post by silverstrom » Wed Nov 04, 2015 11:49 pm

Or get rid of it all and upgrade. If you have to spend money on brakes you might as well spend it on something better than the antiquated early stock brakes. Plenty of options and there are adapters made and sold by members here.

User avatar
two-stroke-brit
-----
-----
Posts: 1701
Joined: Fri Nov 22, 2013 10:49 pm
Location: Houston texas

Re: 84 RZ master cylinder

#5 Post by two-stroke-brit » Thu Nov 05, 2015 12:52 am

I vote for adapters and a whole R1 system.
but were do you stop with the upgrades.
do you keep it with period correct or the whole enchilada.?
350LC,Athena 392 big bore,stock porting,swiss cheese air box,stock reeds,spec11 pipes.(now TSA big bore pipes)
She might not be pretty but she will always be a fun ride


1982 YAMA RD350LC
98KDX 220R
1967 TRIUMPH TIGER
2001 TRIUMPH TT600

User avatar
L.B
Posts: 2008
Joined: Sat Aug 13, 2011 9:59 am
Location: Hunter Valley,Australia
Contact:

Re: 84 RZ master cylinder

#6 Post by L.B » Thu Nov 05, 2015 5:35 am

Triumph '09 -'12 955 calipers bolt straight on & you can use the rz m/c or the 955 m/c as one example.
Another option for seals etc,
http://pages.ebay.com/link/?nav=item.vi ... 60&alt=web" onclick="window.open(this.href);return false;
I have rebuilt a few calipers using these seals with no problems,he also sells ss caliper pistons. While you're at it you can buy ss banjo's & bleed nipples from him.
If you need a sight glass you can try this guy,
http://pages.ebay.com/motors/link/?nav= ... 12&alt=web" onclick="window.open(this.href);return false;

User avatar
L.B
Posts: 2008
Joined: Sat Aug 13, 2011 9:59 am
Location: Hunter Valley,Australia
Contact:

Re: 84 RZ master cylinder

#7 Post by L.B » Thu Nov 05, 2015 5:43 am

Disregard the 955 calipers,they dont fit the 83-84 forks only 85 onwards sorry.

75RD350rider
Posts: 601
Joined: Thu Jun 19, 2014 9:52 pm

Re: 84 RZ master cylinder

#8 Post by 75RD350rider » Fri Nov 06, 2015 10:01 am

What size bore is the stock front master cylinder?
I love the smell of Blue Marble in the morning!
Tim Steele in Front Royal, VA

User avatar
T.RexRacing
Posts: 1318
Joined: Fri Nov 01, 2013 8:34 pm
Location: back in the hills

Re: 84 RZ master cylinder

#9 Post by T.RexRacing » Fri Nov 06, 2015 11:12 am

Bore size is 5/8". Be better off with a 1/2-13MM for OEM calipers. I did upgrade to R1 calipers w/19MM Brembo M/C from an Aprilia Mille. Kept the 220MM OEM rotors though. I want my RZ to appear fairly stock at first glance.
There is only one difference between a madman and me. The madman thinks he is sane. I know I am mad.
Salvador Dali

75RD350rider
Posts: 601
Joined: Thu Jun 19, 2014 9:52 pm

Re: 84 RZ master cylinder

#10 Post by 75RD350rider » Fri Nov 06, 2015 11:34 am

12 or 13 MM? or 1/2? I am unsure what you mean? Thanks T-Rex for your assistance.
I love the smell of Blue Marble in the morning!
Tim Steele in Front Royal, VA

Frank t
Posts: 56
Joined: Tue May 31, 2011 12:04 am
Location: Decatur, AL

Re: 84 RZ master cylinder

#11 Post by Frank t » Fri Nov 06, 2015 11:39 am

Tim,
I upgraded my '82 RD350LC to early RZ350 calipers (same as on your RZ.) At the same time I replaced the stock 16mm master cylinder with a 14mm master. This made a significant difference, the brake lever feel went from hard/no feel to a bit more travel and much more feel.
Frank Tarpley
1988 TDR250, 1974 GT380, 1968 Cobra, 1984/1987 RZ350, 1983 BMW R80st

User avatar
T.RexRacing
Posts: 1318
Joined: Fri Nov 01, 2013 8:34 pm
Location: back in the hills

Re: 84 RZ master cylinder

#12 Post by T.RexRacing » Fri Nov 06, 2015 1:41 pm

13MM is close enough to 1/2" the difference can be ignored for all intents and purposes.
There is only one difference between a madman and me. The madman thinks he is sane. I know I am mad.
Salvador Dali

Frank t
Posts: 56
Joined: Tue May 31, 2011 12:04 am
Location: Decatur, AL

Re: 84 RZ master cylinder

#13 Post by Frank t » Fri Nov 06, 2015 2:18 pm

Tim,
Below is a pic of an '84 RZ with upgraded brakes. It has R1 disc and calipers with adapters available from TDR. Stock MC and forks.
Image
Frank Tarpley
1988 TDR250, 1974 GT380, 1968 Cobra, 1984/1987 RZ350, 1983 BMW R80st

75RD350rider
Posts: 601
Joined: Thu Jun 19, 2014 9:52 pm

Re: 84 RZ master cylinder

#14 Post by 75RD350rider » Sat Nov 07, 2015 3:02 am

Thanks everyone.
I love the smell of Blue Marble in the morning!
Tim Steele in Front Royal, VA

Post Reply