bent brake shoes

[QUIP'6']

well i backed my car out to take for a drive and heard a scraping noise from the rear. drove around the block and returned and removed both wheels and drums only to discover the spring from the adjuster slid of the shoe and was scraping the drum. then apon further inspection the top of the rear shoe was twisted and the round cut out that squeezes against stud in front of the wheel cylinder was bent toward the car and the tops of all the pads the lining was broke off. what would cause this only 2 years old 1000ish miles

 

[QUIP'6']

here are some pix the first 2 are passengerside and the third is the driverside which is not bent as much

 

[chopped39]

I cant see the shoes holding that hard to jam them against the pin and bend them like that.Vacuum conversion wont hold that tight. I want to say they were installed like that but I know that out of the question. Maybe a hard stop at one time? Are the cylinders stock or the bigger ones?

 

[Bill_Ritter]

Mine did the same thing after I installed the s-10 wheel cylinders and a new set of "cheaper " shoes.

 

[turbohh]

I might be able to help....

I have a set of used Praise Dyno Brake shoes with plenty of life left on them, and all the hardware off my GN from my recent conversion to rear discs. I was using the larger S-10 wheel cylinders and didn't have any issues. PM me your email addy if you'd like me to send pix. I marked the shoes frt & rear, and Dr and passenger side.
John A, Turbohh

 

[QUIP'6']

I cant see the shoes holding that hard to jam them against the pin and bend them like that.Vacuum conversion wont hold that tight. I want to say they were installed like that but I know that out of the question. Maybe a hard stop at one time? Are the cylinders stock or the bigger ones?

they are 2 years old and yes they are s10 cylinders. i can hold 15 psi off vacuum brakes. the backing plates are bent at the main lug.

Mine did the same thing after I installed the s-10 wheel cylinders and a new set of "cheaper " shoes.

should i go back to the normal ones

I have a set of used Praise Dyno Brake shoes with plenty of life left on them, and all the hardware off my GN from my recent conversion to rear discs. I was using the larger S-10 wheel cylinders and didn't have any issues. PM me your email addy if you'd like me to send pix. I marked the shoes frt & rear, and Dr and passenger side.
John A, Turbohh

thanks alot but i bought new brakes and new hardware also getting new backing plates. thanks again

 

[QUIP'6']

i dont understand why it would bend there when the shoes move outward

 

[tonka]

Play the animation in this link, a little ways down the page, it should explain what you are seeing:

HowStuffWorks "How Drum Brakes Work"

 

[Bill_Ritter]

they are 2 years old and yes they are s10 cylinders. i can hold 15 psi off vacuum brakes. the backing plates are bent at the main lug.

should i go back to the normal ones



thanks alot but i bought new brakes and new hardware also getting new backing plates. thanks again

I think the reason mine bent was because of the cheap shoes I bought. I was told the cheaper shoes were softer material and would hold more boost at the line.

I was foot braking and using the ebrake, to hold 15psi on launch when mine bent. Mine also bent the backing plate and pin, as well as the rear end housing flange that the backing plate mounts to. Needless to say, I dont used cheapy shoes anymore and havent had any more problems.

 

[Chuck Leeper]

Cheezy backing plates....
W/ enuf brake line psi to hold 15# of boost, the back plates got hammered just like many that did with using the park brake to launch...

 

[TurboBuRick]

Damn, your rough on brakes. :biggrin:

Thats where a 2-step comes in handy. Build all the boost you want without loading the chit out of the brakes. It's a beautiful thing.

 

[QUIP'6']

i never used the e brake for building boost! i couldnt imagine what they would look like if i did. yes the 2 step soulnds nice just waiting for the new ccci to come out from big bad bob bailey

 

[Nick Micale]

I cant see the shoes holding that hard to jam them against the pin and bend them like that.Vacuum conversion wont hold that tight.........................

This is a MAJOR mis-conseption. The vac conversion will actually send more pressure to the rear brakes than a PM.

At least in the mid-90's when I first started doing vac conversions, it was once motivated by a customer complaining of poor braking, stopping distance.

Before I removed the PM, I did a test of locking the brakes at 35 MPH, and only had skid marks from the front tires [and prior to this I had adjusted the rear shoes].

A few hours later after the conversion to a vac booster and master cylinder, the test was conducted again. This time there were 4 equal length tire patches, and the stopping distance was shorter.

We have verified this a few more times over the years.

As to the original problem of bending the brake shoe, in my shop a rear drum brake job would always receive a new hardware kit which includes new, fresh springs.

So, if your hardware was not replaced 2 years ago, this could be a factor in why that happened.

 

[QUIP'6']

This is a MAJOR mis-conseption. The vac conversion will actually send more pressure to the rear brakes than a PM.

At least in the mid-90's when I first started doing vac conversions, it was once motivated by a customer complaining of poor braking, stopping distance.

Before I removed the PM, I did a test of locking the brakes at 35 MPH, and only had skid marks from the front tires [and prior to this I had adjusted the rear shoes].

A few hours later after the conversion to a vac booster and master cylinder, the test was conducted again. This time there were 4 equal length tire patches, and the stopping distance was shorter.

We have verified this a few more times over the years.

As to the original problem of bending the brake shoe, in my shop a rear drum brake job would always receive a new hardware kit which includes new, fresh springs.

So, if your hardware was not replaced 2 years ago, this could be a factor in why that happened.

yes they were the original ones

 

[QUIP'6']

took off the backing plates and found that my driverside axle flange is bent in at the upper front corner in 3/8 of an inch.