rear brakes pulsating.....ideas

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Adam
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rear brakes pulsating.....ideas

Post by Adam » Wed Oct 12, 2011 9:43 pm

2011 gear up here. 2301 kms. All types of roadway miles, highway, traffic, etc. Never had the hack wheel off the ground. Never have hit anything with the hack wheel. Shock is adjusted second notch from the tightest setting.

I started to notice when braking, the hack would make the bike pulsate to the right. After jacking the hack up and spinnin the wheel, while applying the brakes, something seems out of round. The brakes grab in a certain spot then the wheel free spins until it hits that same spot, that is while appling a lil brake. I then yanked the spare off the hack, wiped the drum off with a clean rag, installed it and same thing happened. So to me that cancels out the drum being out of round. I tried spinning the driveshaft to see if its bent at all but hard to do. I will be putting a dial indicator on it tomorrow to see. Then out of curiousity I spun the pusher wheel and applied a bit of brake, that too has a spot in it. Hmmmm..........any thoughts? Any fixes?

I prolly need to adjust the pusher brakes to be stronger, and the hack brakes a little less. I have not adjusted anything on my brakes yet.

Thought I would share and see what suggestions come my way. I will feel better after checking the shaft with a dial indicator. I will be posting my results tomorrow evening.

Adam
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Tarka
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Re: rear brakes pulsating.....ideas

Post by Tarka » Thu Oct 13, 2011 2:24 am

So..you`ve checked two hubs but have you inspected your brake shoe linings?

How worn are they...how much adjustment have you made via the brake rod adjuster nut?
Maybe you`re at a point where a high spot is causing some drag.

If you`ve used most of your brake rod adjustment it would be prudent to back it all off then adjust the spread of your brake shoes via their adjustable feet and the chalk method to ensure even application and no high spots.
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Re: rear brakes pulsating.....ideas

Post by S 854 » Thu Oct 13, 2011 6:11 am

Adam wrote: I then yanked the spare off the hack, wiped the drum off with a clean rag, installed it and same thing happened. So to me that cancels out the drum being out of round.
Wiping yer drum with a rag won't 'cancel out the drum being out of round'... if the symptoms don't occur with the brake shoes not in contact with the drum and appear once again as you apply a little braking action... yer drum is out of round... it's been known to happen... mine were... it's an easy fix...
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Re: rear brakes pulsating.....ideas

Post by heindlengineeringural » Thu Oct 13, 2011 8:12 am

Sounds like an issue with either the drum or the shoe. We have have shoes in the past that needed to be turned around and order to wear in properly.
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Re: rear brakes pulsating.....ideas

Post by MartyL » Thu Oct 13, 2011 9:17 am

My sidecar wheel is doing the same thing when cold. When it heats up it's much better. I had Holopaw Gene do a little grinding on the drum last year to try and cure it but I still got the cold pulsating. I will do the chalk test when I get the chance. I got a feeling that it's either the shoe adjustments or the drum is out of round. I'll take pics of what I do and do a post on it...
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Re: rear brakes pulsating.....ideas

Post by doug » Thu Oct 13, 2011 9:36 am

S 854 wrote:
Adam wrote: I then yanked the spare off the hack, wiped the drum off with a clean rag, installed it and same thing happened. So to me that cancels out the drum being out of round.
Wiping yer drum with a rag won't 'cancel out the drum being out of round'... if the symptoms don't occur with the brake shoes not in contact with the drum and appear once again as you apply a little braking action... yer drum is out of round... it's been known to happen... mine were... it's an easy fix...
He put on a different wheel (the spare) and got the same symptoms - I would tend to agree with him that that would indicate it wasn't an out of round drum.

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Re: rear brakes pulsating.....ideas

Post by sputnik » Thu Oct 13, 2011 12:36 pm

All of my drums were out of round new. Now after 30,000k they are true. have em trued up ona drum lathe if it bothers that much..

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Re: rear brakes pulsating.....ideas

Post by TheWildOne » Thu Oct 13, 2011 6:07 pm

...or just call it "inherent ABS" and fuggedaboudit. (sorry - couldn't resist)

I suppose it's also conceivable that both your hack & spare drums are out-of-round. If 'twere me, I'd try swappin' the pusher & hack wheel and see if the pulsation moves to the pusher.

I wonder - could you feel the pulsation at the brake pedal ? Or was it just kinda pulse/pulling on the bars ?

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Re: rear brakes pulsating.....ideas

Post by cdscoot » Thu Oct 13, 2011 7:36 pm

S 854 wrote:
Adam wrote: I then yanked the spare off the hack, wiped the drum off with a clean rag, installed it and same thing happened. So to me that cancels out the drum being out of round.
Wiping yer drum with a rag won't 'cancel out the drum being out of round'... if the symptoms don't occur with the brake shoes not in contact with the drum and appear once again as you apply a little braking action... yer drum is out of round... it's been known to happen... mine were... it's an easy fix...
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Re: rear brakes pulsating.....ideas

Post by Lokiboy » Thu Oct 13, 2011 8:36 pm

Adam,

Had he same issue when I rotated my wheels at 5K. Now at 6,500K I don't notice it. I too thought the drum was out of round. I swapped the tires back and forth -- same problem. So, I decided since it really didn't impact my stopping, and I really only noticed it at slower speeds not to do the chalking etc. So, for what it's worth, I'd let it go and see if it smooths out.
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Re: rear brakes pulsating.....ideas

Post by isldtime » Thu Oct 13, 2011 10:02 pm

Spoke torque could be an issue. It was on mine. I added humungus pulsation while trueing the wheels.
Backed off a bit and it was much better on old square Russian wheels.
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Re: rear brakes pulsating.....ideas

Post by S 854 » Fri Oct 14, 2011 7:44 am

cdscoot wrote:What is the EASY fix?
I did this about 25K back... so far it's workin' ... :oops:
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Re: rear brakes pulsating.....ideas

Post by Adam » Sat Oct 15, 2011 11:03 am

Used a dial indicator on the short axle (shaft the wheel slides on) everything is good there. I am blaming the drums otta round. Going to run it for a while and mention sumtin to my dealer. I have it set now so the pusher does most of the braking.

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