Author Topic: Brake rebuild on 73 cb500  (Read 982 times)

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Offline tennesseebreeze

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Brake rebuild on 73 cb500
« on: July 31, 2014, 11:10:59 am »
I want to rebuild the brakes on my 73 cb500. Anybody have an affordable source for a rebuild kit and advise on making the brakes as good as they can be? I'm thinking about stainless hoses too.
'79 CB750F, '73 CB500K2, '78 CB400A, '71 CL100

Offline goldarrow

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Re: Brake rebuild on 73 cb500
« Reply #1 on: July 31, 2014, 11:26:32 am »
tip:  good and thorough cleaning. 
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Offline riverfever

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Re: Brake rebuild on 73 cb500
« Reply #2 on: July 31, 2014, 03:13:32 pm »
This was one of the first issues I needed to address on my bike. With only one brake up front I wanted to go through it thoroughly and make sure it worked really well. MC rebuild kit can be had from David Silver Spares (you will need a good pair of snap ring pliers to do this job). Stainless lines can be bought from Carpy, Dime City (I think) and Slingshot. If you need a new caliper piston you can also get that from DSS as well as the piston oil seal. Lastly, you will need some high vacuum grease for the back of the pads. You can find that on ebay.

http://www.ebay.com/itm/DOW-CORNING-Laboratory-High-Vacuum-Grease-976V-Stopcock-/280617417916?pt=LH_DefaultDomain_0&hash=item415619fcbc

The job is pretty straight forward.
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Offline calj737

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Re: Brake rebuild on 73 cb500
« Reply #3 on: July 31, 2014, 03:26:28 pm »
Check with Godferrey for a phenolic piston as an alternative to steel. Slingshot for your brake lines and fittings, and clean that internals to a spotless condition.
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Offline Stev-o

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Re: Brake rebuild on 73 cb500
« Reply #4 on: July 31, 2014, 07:40:06 pm »
What are the current issues with your brakes?
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline speedwolf

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Re: Brake rebuild on 73 cb500
« Reply #5 on: July 31, 2014, 09:51:07 pm »
'72 Honda CB500 K1

Offline tennesseebreeze

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Re: Brake rebuild on 73 cb500
« Reply #6 on: August 01, 2014, 05:33:46 am »
What are the current issues with your brakes?

The brakes haven't even been tested yet, but are definitely in need of service. The entire bike was in bad shape when I got it. The brake system has cracked brake lines, residue inside and around lever, rusty bolts, etc. I've had to  replace just about every other rubber part on the bike, so I wouldn't expect anything less of the brakes. I've got the whole bike in pieces and I'm going through every part.

I can take some pictures of the brakes if that will help. To tell me to give it up already.
'79 CB750F, '73 CB500K2, '78 CB400A, '71 CL100

Offline calj737

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Re: Brake rebuild on 73 cb500
« Reply #7 on: August 01, 2014, 06:32:28 am »
Your plan sounds appropriate. May be easier and more successful simply replacing master cylinder with an OEM than attempting to rebuild if it's as bad as you describe. But the caliper can be rebuilt provided no cracks in bleeder or hose attachments.
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"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline Stev-o

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Re: Brake rebuild on 73 cb500
« Reply #8 on: August 01, 2014, 06:44:49 am »
Your plan sounds appropriate. May be easier and more successful simply replacing master cylinder with an aftermarket unit from DSS

Fixed that for ya, Cal.


https://www.davidsilverspares.com/CB750K4-FOUR-1974-USA/part_123914/
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Offline tennesseebreeze

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Re: Brake rebuild on 73 cb500
« Reply #9 on: August 01, 2014, 06:52:10 am »
Yeah, I'll be thinking about replacing that MC. I do like the patina those old ones have, but it sounds like a master cylinder rebuilt can be hit or miss, mostly miss.

Thanks for all the resources guys- very helpful.
« Last Edit: August 01, 2014, 07:06:07 am by tennesseebreeze »
'79 CB750F, '73 CB500K2, '78 CB400A, '71 CL100

Offline jamesbekman

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Re: Brake rebuild on 73 cb500
« Reply #10 on: August 01, 2014, 08:46:37 am »
Ive never heard of using high vacuum grease.  Why would you apply it to the back of the brake pads?  Do you mean to the piston seal?

-James

Offline Chachi

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Re: Brake rebuild on 73 cb500
« Reply #11 on: August 01, 2014, 09:10:32 am »
That DSS MC is good. It's plug and play and looks original. You could also possibly fit your original cap on it. DSS has repro outer caliper bodies (and pistons) too if the one you are working with is too far gone. I like Slingshot for stainless (or rubber) lines. He has banjo bolts, crush washers and speedbleeders. Banjos and speedbleeders are available in stainless too. I use EBC pads. Most common replacement. Usually have to sand the paint from outer rim of pads to fit calipers properly.

The high vacuum grease on the back of the pads... I used it on my rebuild. There are several posts on it, but I believe it's purpose is twofold: (1) to keep moisture/gunk away and (2) to possibly help reduce squeal. It has been tested a lot here and the grease doesn't 'run' when hot and get on pads, etc. I put it on the back of my pads and a little on the metal side walls. Just be careful and don't get it on the pad surfaces.
« Last Edit: August 01, 2014, 09:12:07 am by Chachi »
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Offline calj737

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Re: Brake rebuild on 73 cb500
« Reply #12 on: August 01, 2014, 09:14:31 am »
Ive never heard of using high vacuum grease.  Why would you apply it to the back of the brake pads?  Do you mean to the piston seal?

-James

^^^^As Chaci said. Regarding the seal, only use Brake Assembly lube on it.
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"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline Chachi

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Re: Brake rebuild on 73 cb500
« Reply #13 on: August 01, 2014, 10:15:13 am »
Ah yeah, forgot that. I think I used Willow wood assembly lube on the piston seal and Dow made the high vacuum grease I used.
73 CB750 K3
72 CB500 K1 - Sold
75 MR50 Elsinore K1