1980 Rear Brake

[busaboy]

I'm having trouble rebuilding the rear brake on my 80.

The piston is about 33mm diameter, vice the ca. 37mm diameter pistons in the (what I earlier thought were identical) front brakes.

I am finding it difficult finding a new piston and seal kit for the rear. Can anyone help me in sourcing these parts?

Finally, I wouldn't mind buying a good used rear brake, if anyone has one for sale.

thanks

[Terry]

Check the board for brake info by Tom Whaley in Oregon. I think he had some great brakes for sale recently.

[Terry]

What the...

[Ron#5602]

Check with Louis, I'm sure he'll have a good used rear brake assy. much cheeper than you could find the parts for.

Ron#5602

[Tom Whaley]

Eric, You can use several different rear brake setups on your early model. The CB750F, CB900F, Late Model CBX all will interchange with yours. There are others but you get the idea. They all use the same caliper mount and they will all bolt directly onto your early model. The good part is you will have duel piston calipers and parts are readily available for them. I hope this helps. :)

[busaboy]

thanks to all for the assistance.

Tom - I knew about the 750F brake interchangeability, but not the others - and I never thought about using the later CBX rear brake as a replacement!

Can I use my existing rear master cylinder with that and the other calipers?

How about the front calipers? Are they similarly interchangeable? Can I use the existing front master cylinder with late model front calipers?

Thanks again!!

[Dave Krager #5383]

Hi Eric,

You can use your existing master cylinders both front and rear the only Thing that needs to be changed out in addition to the calipers is the attachment brackets. I am using a set of 82 goldwing calipers on the front and the rear I think is from a 900F but Tom would know that one for sure since I got the rear from him. BTW his calipers are immaculate. He is a total neat freak when it comes to that kind of stuff. The dual piston setup is a most excellent upgrade and certainly worth considering.

Hope this helps.

Dave

[Tom Whaley]

Hi Eric,

There is several models that use that rear brake caliper mount for the twin piston calipers. Like Dave said the master cylinders will all work with single or twin piston calipers. In most cases the right front caliper will interchange with the rear caliper. There is a few exceptions to watch for though. Sometimes the bleeder is in the wrong place to bleed the brakes and some rear calipers have a tab that the rotor fender hooks onto. I have a Interceptor twin piston caliper on the rear of my "79" and the bleeder is on the bottom so I bled the brakes before I installed the caliper. I just held the caliper so the bleeder was at the top. If you put the duel piston calipers on the front you might as well use the "F" style rotors also. The brake pads are narrower so Honda cut slots in the area where the pads don't rub. You loose a little un-spung weight and they look better than stock. I hope this helps you some.

[busaboy]

All this is very helpful!!

Tom - your comment that the right front caliper on my bike should interchange with the rear is what I expected before I started this job. Most documentation we have looked at here indicate that the internals on all these brakes are the same - I presume you would expect the rear piston to be the same size as the fronts? Do you have any idea what might be going on here? Did someone possibly exchange the caliper some years ago ( I have only had it since 1992)? Was this possibly some running change, or perhaps Honda was using up some extra parts?

However, going back to my original problem - the piston (and bore and seals) on my existing rear brake are about 4-5mm smaller than the fronts. The rear caliper LOOKS exactly like the right front, but the guts are just a little smaller!! Do we all agree this is unexpected?

thanks-

[Tom Whaley]

Eric, Looking in my trusty Honda shop manual it says that the "79" has 42.772mm pistons in the front brakes and a 38.098mm piston in the rear. I looked in the "80" ADDENDUM and it gives me no further information. I then went to TIMS catalog and it says both caliper pistons front and rear on the "80" model are the same at 42.772. It seems that our numbers are several mm's apart You might have a "79" rear brake caliper on the rear of your "80". When I mentioned that the right front will interchange with the rear I was talking about the duel piston calipers like the late model calipers. You asked about using the late model brakes on your early model They will work but I would recommend using the late model rotors also. The calipers and caliper mounts are designed for the much thicker ventilated rotors. Actually I wouldn't reccomend using the late model brakes at all. I removed my late model front calipers and rotors and went to a 16" front wheel and loss 14lbs. in the process. I seem to learn something new every time I start messing around with the CBX brakes. If I can be of any more help just send me a E-mail and I'll try and answer your questions.

[ken79]

Tom,
Speaking of brakes for the 79 CBX, what ever happened to the PM
brake calipers and master cylinder selections in Tims catalog? I have
an old catalog with those listed, and a new catalog without. The time
between being several years, I was surprised to not see that option.
Do you know if you can still order them elsewhere, or are there better,
more practical solutions? The reason I'm wondering is because I still have
stock brakes on my project bike, and while I don't push too hard, I had
thought of improving my braking options. Any information would be
appreciated.


Ken

[Tom Whaley]

Ken, I'm not sure if TIMS is even in business any more I don't even know about the PM Brakes either So much for help from dumb old Tom But There is other options for you to look at. Like I posted before the "F" model brakes are a big improvement at a much smaller cost. If you are building a show stopper they won't look showie enough I'm sure. I forget to mention that one model of the Goldwing breaks are the same as the "F' models. One of the most interesting things I noticed is that most of the Hondas in the late seventies to mid eighties all have the same dimensions from center to center on the brake rotors I'll mention again that I have a VF1000F Interceptor front wheel on my "79" CBX and a "81" CBX front end. To top it off I have a set of CBR600F Hurricane rotors bolted onto the VF wheel. Oh yeh I have the 32mm Interceptor calipers bolted onto the "81" front end. Point is all of these parts interchanged without a hitch :) The only alterations I had to do was to manufacture fender mounts so I could use the Interceptor front fender. So if you could find some rotors that you like that will fit some of these old Honda's they should work on your project bike. I hope this helps.

[ken79]

Tom
Thanks for the information on the brakes. I was following the previous
posts about the F model Hondas. And "no", the bike will not be the show
stopping type. It will look nice, but I won't be afraid to ride it for fear
of scratching the paint.
Does anybody know if Tim's is still in business I know(or
think I know) that Tim sold the business to some people in Tenn., but
I have no idea if they've managed to stay in business. I hope so .
Are there any other dedicated CBX businesses out there besides CBX
Performance in Costa Mesa, CA.?
This is what happens when you get away from your bike for several years,
the world changes for the worse Any information would be appreciated.


Ken

[busaboy]

Tom - thanks.

I have measured all these pistons...the fronts on my bike are 38mm, give or take a few tenths; the troublesome rear is 33mm, give or take a little. I expected it to be the same as the front, and so did everyone except my bike, apparently!

Norma is liquidating Tims' inventory, they are going out of business because of her hubby's health problems. I have talked with her as recently as three days ago. You can still buy stuff if it's on their shelf.

I also have noticed that some of the neat stuff that used to be in Tim's catalog, such as the PM brakes, are gone. Those PM brakes were going to be one way out of my dilemma.

PM is very much still around, I think. They are big into Harley stuff, and I continue to see their ads.

[SS]

Ken:

Does anybody know if Tim's is still in business I know(or
think I know) that Tim sold the business to some people in Tenn., but
I have no idea if they've managed to stay in business. I hope so .
Are there any other dedicated CBX businesses out there besides CBX
Performance in Costa Mesa, CA.?

Alex & Norma purchased Tim's. I spoke with Norma (@ Tim's) less than two weeks ago, they are still in biz, albeit without a large inventory. I Also received a credit (Norma promptly issued my credit to CC) for an item I purchased in Feb. & returned in Mar.

Tim's has been open M-F 4:00 PM - 7:00 PM CST. My last conversation with Norma regarding their business future, she stated " I think we have the business sold, and if things go well @ the lawyer's office, the sale could be complete by the end of Mar."

I also chatted with Chuck Ewing yesterday AM, (yes he did speak with me, even though it wasn't Mon. or Tues. his normal CBX days ).
He told me he was also in the process of selling his business, and wasn't (at that point selling his CBX parts because of the sale arrangements).
He gave me almost no details about his sale.