Author Topic: rear brakes dont work.. (Read 4936 times)

73nancy · « **on:** April 19, 2010, 09:32:25 AM »

hey guys i got a issue with my rear brakes. the guy i bought my bike from took the stock pedal off the bike so i bought a new one, but the issue i have is the rear brake drum arm is bent i think its supposed to be straight. as well as the threaded rod i think is not correct because it bends when the brakes pushed. just want to get it back to normal but i dont know what its supposed to look like. if anyone can take some pics for me of there rear brake so i can tell whats wrong with mine. thanks a bunch ryan

madmtnmotors · « **Reply #1 on:** April 19, 2010, 09:39:14 AM »

If the brake rod is bending then the brake pedal pivot pin (where the brake rod connects) is upside down. Remove the pedal, disconnect the brake rod, rotate the pedal pivot so the brake rod connects ABOVE the pivot rod, not below. If the rod is bending then it is in compression (push) instead of pulling (like it should).

73nancy · « **Reply #2 on:** April 19, 2010, 09:41:51 AM »

good advice.. i def have to check that out today.

MCRider · « **Reply #3 on:** April 19, 2010, 09:58:41 AM »

Quote from: 73nancy on April 19, 2010, 09:32:25 AM

hey guys i got a issue with my rear brakes. the guy i bought my bike from took the stock pedal off the bike so i bought a new one, but the issue i have is the rear brake drum arm is bent i think its supposed to be straight. as well as the threaded rod i think is not correct because it bends when the brakes pushed. just want to get it back to normal but i dont know what its supposed to look like. if anyone can take some pics for me of there rear brake so i can tell whats wrong with mine. thanks a bunch ryan

What bike? Assuming a 750 in your avatar? Pictures would be nice. I've seen many here install the pivot arm, the splined piece that the pedal mounts to, incorrectly. They put the pull arm below the swingarm. It shold go between the swingarm and the frame.

The brake pedal has a dot on it where the splines are. That dot should align with the dot on the splines on the pivot. Same for the brake arm on the drum. If these are mounted properly it is usually apparent how the pull rod lashes up.

73nancy · « **Reply #4 on:** April 19, 2010, 01:37:34 PM »

ya its on a k1 750. i get some pics of it up tonight.

madmtnmotors · « **Reply #5 on:** April 19, 2010, 06:46:46 PM »

Okay here's some picts. The arrows in picture 4 show how the rear brake rod tucks between the swingarm and the frame above the brake pivot on my CB750K8.

MCRider · « **Reply #6 on:** April 19, 2010, 07:04:32 PM »

Can't see anything definitive. The pedal adjuster bolt on the far right of #4 seems to be way out there. The pedal should be nearly horizontal with very little of that adjuster bolt extended.

But that's likely a non-relevant detail. Sorry. Hope someone else has an idea.

madmtnmotors · « **Reply #7 on:** April 20, 2010, 04:06:54 AM »

Yeah, I believe I've got the pedal rotated downward by one tooth on the spline shaft. My size 12's command alot of room and I find the pedal position more comfortable. Anyway, when the pedal pivot is installed correctly it is nearly impossible to see the connection point between the brake rod and the pedal pivot since the connection is tucked way up close to the swingarm pivot. Your description of the bending rod leads me to believe the connection for the brake rod is below the pedal pivot (180 degrees off). I seem to remember installing mine that way once and do not have any fond memories of the corrective measures. Don't remember whether the centerstand and/or swingarm had to be removed, or if it was just a matter of taking the pedal off and rotating the pivot pin to it's correct position. I think the sticking point might be that the pivot pin had to be removed in order to correctly orient the coiled return spring on the inside of the frame. It seems to me that in order to install the pivot pin 180 degrees off that the coiled return spring had to be flipped. My recollections are pretty vague since my "Wrong way brake" guffaw had to be at least 15 years ago...

Were you going to post picts of your brake rod setup?

After looking back at my pictures (pict 4) I'm pretty sure the pivot pin can be removed WITHOUT removing the swingarm or centerstand.

Johnie · « **Reply #8 on:** April 20, 2010, 05:43:50 AM »

You for sure have an aftermarket or different year brake arm on the hub there for a K1. I have included a pic of my K1 brake arm where it attaches to the brake pedal for reference for you. There is also a pic of the OEM brake arm attached to the hub. In looking at the arm on the wheel hub it looks like the bend is more to the right than on the OEM K1 arm. Click the pic to enlarge...

madmtnmotors · « **Reply #9 on:** April 20, 2010, 06:40:50 AM »

Yes, the brake arm at the rear hub is different than a K1 since mine is a K8...

Excellent picture from the opposite side by the way...

Johnie · « **Reply #10 on:** April 20, 2010, 07:31:18 AM »

Quote from: madmtnmotors on April 20, 2010, 06:40:50 AM

Yes, the brake arm at the rear hub is different than a K1 since mine is a K8...

Excellent picture from the opposite side by the way...

Gottcha...I thought those were the pics of the K1.

madmtnmotors · « **Reply #11 on:** April 20, 2010, 09:09:33 AM »

I'll get the posts mixed up too, especially those without an avatar, so I've added one to my profile.

I think with your pict from the opposite side should get 73nancy on the right track.

bryanj · « **Reply #12 on:** April 20, 2010, 01:23:25 PM »

If your pedal is pushing the rod to operate the brake its put together wrong

73nancy · « **Reply #13 on:** April 20, 2010, 09:35:12 PM »

k guys took some pics. the bike is bare frame but i think you will get the idea.

also is the rear brake arm that goes to the hub is bent? i think its supposed to be straight.

MCRider · « **Reply #14 on:** April 20, 2010, 11:28:17 PM »

The pivot that the brake pedalis on is UPSIDE DOWN! The part that the rod hooks to points up not down. If you line up the dots I mentioned in a previous post you'll see.

Once the pivot lever is repositioned UP, between the swingarm pivot tube and the frame, you'll see it PULLS, not pushes.

If you look to the right side of picture 2, the right side of the pedal where it has its splines, there will be a dot. And the splined end of the pivot lever has a dot. They must lin up.

MCRider · « **Reply #15 on:** April 20, 2010, 11:51:00 PM »

Additionally, the long rod has threads going into the pivot arm. This is wrong, the stock rod doesn't have threads there. But if your threaded rod is long enough, after flipping the pivot arm, you could still use it I guess. Is yours threaded the entire length? If so, it is definitely wrong part.

The rear brake arm that goes to the hub is probably not bent. But I have a K2 and will look tomorrow, its the same as K1. Maybe it does drop straight down.

Johnie · « **Reply #16 on:** April 21, 2010, 04:54:44 AM »

Are you trying to put this K1 back together using K1 parts? Or are you using anything you can find? I take it this will be a custom bike using the parts I see here. If so, you will have to do some tweaking as the build progresses. If you take a look at the pics I posted earlier you will see how both arms are to be positioned. Might try to get a service Honda manual as they have good pics to help you along.

madmtnmotors · « **Reply #17 on:** April 21, 2010, 05:53:06 AM »

Quote from: MCRider on April 20, 2010, 11:28:17 PM

The pivot that the brake pedalis on is UPSIDE DOWN! The part that the rod hooks to points up not down. If you line up the dots I mentioned in a previous post you'll see.

Once the pivot lever is repositioned UP, between the swingarm pivot tube and the frame, you'll see it PULLS, not pushes.

If you look to the right side of picture 2, the right side of the pedal where it has its splines, there will be a dot. And the splined end of the pivot lever has a dot. They must lin up.

Sounds familiar....

73nancy · « **Reply #18 on:** April 21, 2010, 09:58:30 AM »

thanks a bunch guys. ya the rod is just something you find in the hardware store. i want to put it back to stock form as much as posible. do you guys know where i can find a a stock brake rod. i will def flip it around when it goes back togeather.

MCRider · « **Reply #19 on:** April 21, 2010, 10:09:00 AM »

I thought that may be a piece of "all-thread". The stock rod is only threaded at the wheel end about 3-4 inches. The front end is some other attachment to the curved fork affair.

I may have a spare rod, I'll check tonight. I'd have to charge for it though as that's how I finance my own build. Don't wait for me though. If you find a freebie or a good price, jump on it. There's probably one around somewhere. The chopperized and stretched bikes need longer rods often.

73nancy · « **Reply #20 on:** April 21, 2010, 10:26:47 AM »

ya def i putting a ad in the wanted section.. but ya if you have a spare i buy it off from you.

MCRider · « **Reply #21 on:** April 21, 2010, 07:04:58 PM »

I don't have one (that I can find

)

One on eBay for $10. + $10S&H

http://cgi.ebay.com/ebaymotors/1973-Honda-CB750-CB-750-Rear-Brake-Rod-_W0QQcmdZViewItemQQhashZitem33515ab6b3QQitemZ220408231603QQptZMotorcyclesQ5fPartsQ5fAccessories

Here's how much offset the rear brake panel arm has

Here's some perspective on where the pedal pivot arm goes:

Rr brake panel arm again:

PS: I like your frame color choice.

73nancy · « **Reply #22 on:** April 21, 2010, 08:45:58 PM »

thanks a bunch ya i might try and buy one soon.. ya the gold frame was something not many were doing now it seems many of us are finishing bikes at the same time so im seeing more of them.

MCRider · « **Reply #23 on:** April 21, 2010, 08:54:44 PM »

Quote from: 73nancy on April 21, 2010, 08:45:58 PM

thanks a bunch ya i might try and buy one soon.. ya the gold frame was something not many were doing now it seems many of us are finishing bikes at the same time so im seeing more of them.

I was planning the gold frame 10+ years ago. But its a free country. Yours appears to have some metallic in it?

Mine is a silver metallic base coat with candy gold overcoat, powdercoat. The metallic really "pops" in the sunlight.

73nancy · « **Reply #24 on:** April 22, 2010, 09:52:21 AM »

ya def.. i love the gold frame look.. ya the way i look at it we are all over the country and they wont be all the same like if you were to buy a new bike.
mine is a dupont gold glow powder coat. it has metalic in it for sure. i like the shade you have. mine is very hard to match so my engine has gold paint but is much more yellow but i dont mind.

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Author Topic: rear brakes dont work.. (Read 4936 times)