HighcountryMike's parking brake project

[posplayr]

Originally Posted by Ben10281

This is interesting, I replaced my parking brake shoes last year, and my parking brake works waaay better now. However, some days when I press on the pedal it barely pushes in before grabbing tight, and other days it will push all the way to the floor. The parking brake is tight in both scenarios, but I wonder if the differing pedal positions is due to a misfitting brake shoe!

I would guess the shoes are binding prematurely (in terms of pedal stroke)sometimes and not against the drums. That would mean you don't actually have brakes when you have a firm pedal.

[arctictraveller]

Originally Posted by posplayr

They look to be pretty good match (withing only 0.020" at the ends) except the last 1-2" of the shoes. I don't know if that is on purpose or not but at least it seems to be 70-80% matched.

I doubt its on purpose. When matching shoes to the drum using a machine, 100% contact is the goal with the exception of a slight ramp on the leading edges.

[arctictraveller]

Originally Posted by Ben10281

However, some days when I press on the pedal it barely pushes in before grabbing tight, and other days it will push all the way to the floor. The parking brake is tight in both scenarios, but I wonder if the differing pedal positions is due to a misfitting brake shoe!

That's interesting, I'm trying to imagine how that's happening. I doubt it's due to the fit of the shoes, since they never really change except as they wear. Something has got a lot of play in it, but without seeing it in person I can only guess that the star wheel adjuster is quite loose so it occasionally comes partly out of the groove it fits in and that takes up the play. Otherwise, I'm at a loss to explain how it changes. If it were me, I'd pull the wheel and check it out since it's possible that what ever is causing the play could end up causing the shoes to get stuck in the applied position at some point.

[posplayr]

Originally Posted by arctictraveller

I doubt its on purpose. When matching shoes to the drum using a machine, 100% contact is the goal with the exception of a slight ramp on the leading edges.

Well, they are close enough that I'm not sure how to measure and I doubt I could shave them down with a flap disk and not make it worse.

That said, they are probably OE spec meaning the shoes have been shaped for the OE stock drums.

The issue you were dealing with could certainly occur if fitting new shoes into old disks. If both are new they should be an OE fit (as good/bad as that might be).

[boywonder]

The turnbuckle mod is interesting......

Mike's shoes were clearly contacting the drums mostly on the side where the cable actuator is....as expected. The other end of the shoes aren't doing much.

In the old days a few motocross bike brakes had "dual leading shoes" they worked really well....

Originally Posted by BrianW

Are the 2008+ REAR brakes larger than previous years? I thought it was only the front brakes that are larger?

I did some searching on Rockauto.com....

2003 rear rotor dia 12.83"
2008+ rear rotor dia 13.58"

2003 Parking brake shoe/drum dia 8.07"
2008+ Parking brake shoe/drum dia 8.9"-9" depending on who's data sheet your read.

[arctictraveller]

There is a good explanation of how and why brake shoes are matched to drum size in this video, starting at about the five minute mark.

https://www.youtube.com/watch?v=d8f9PfrMWss

[posplayr]

Originally Posted by arctictraveller

There is a good explanation of how and why brake shoes are matched to drum size in this video, starting at about the five minute mark.

Thanks for finding that video, but I assume you also looked at some way of accomplishing the surfacing without spending $500; it doesn't seem to exist.

I rechecked my rear disk with a shoe clamped into the drum. I used a thin feeler gauge that is probably 0.002-0.004" (I could not read the numbers but I can arch it a little) . It doesn't fit in about 1/2 the arch of the shoe, so it is close. The shoes were clearly surfaced with a machine intended for the purpose. For me I'll just have to settle for aftermarket "OE spec"

I will have to just bed the shoes in a few times once installed, to get a better fit. That will be more reliable than me using a flap wheel.

[boywonder]

Originally Posted by posplayr

I will have to just bed the shoes in a few times once installed, to get a better fit. That will be more reliable than me using a flap wheel.

Yes..that seems to work quite well......forwards and backwards

[arctictraveller]

[QUOTE=posplayr;329595]Thanks for finding that video, but I assume you also looked at some way of accomplishing the surfacing without spending $500;"

I agree, I have not seen a shoe arc grinder in 40 years. I think someone here mentioned putting a strip of emery cloth inside the drum then pressing the shoe into it and rotating it back and forth to get closer to the diameter of the drum.


"I rechecked my rear disk with a shoe clamped into the drum. I used a thin feeler gauge that is probably 0.002-0.004" (I could not read the numbers but I can arch it a little) . It doesn't fit in about 1/2 the arch of the shoe, so it is close."

It sounds like you mean you have about 50% of the shoe in contact with the drum. Obviously, more is better, but if it currently holds to your satisfaction, why worry?

In my case, in the beginning, when applied really hard, it would barely hold when I put it in gear at an idle. Eventually I ended up accidentally driving on the freeway with it applied and burned up the shoes along with putting hot spots on the disc. After that I was determined to make it work properly and finally got the new setup to hold pretty well, so now it's obvious if I try to drive away with it applied. (unless I'm in 4 low)