The Daily Yardman Thread

[Ronno6]

Re: MTD Yardman Transaxle Rebuild

I had a persistent intermittent issue with one of the rear brakes on my 85 k20 hitting hard/locking up. I never did resolve the issue. It sure was fun doing the back half of my snow plowing route when the line for the front brakes blew out leaving me with just the rears. Can you guess what happens when you lock up one rear brake in the snow?

WHEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE.....................

 

[Boobala]

Re: MTD Yardman Transaxle Rebuild

My '84 C10 Chevy has a mixture of braking systems.
The VIN indicates that the truck came from the factory with a 4001-5000 GVW brake system, which is the lighter duty setup.
The front has the heavier duty 1.25" rotor and wider caliper, tho the piston bore is the same as the lighter duty 1" rotor.
It also has a double diaphram vacuum booster from the HD system.
The rears are light duty 11x 2 shoes/drum w/1" bore cylinders. (the HD system uses 11.15 x 2.75" shoes/drums, but smaller 15/15" bore cyls.)
I have replaced calipers, drums,rear cylinders, master cylinder (2x) and combination valve.
Bled, rebled, rebled again, and again...........Finally doing a gravity bleed.
Original problems were:
1.pedal mushy.
2.Rear drum brakes locking up.

Gravity bleed finally helped the mushy pedal, but the rear lock-up persists.
I even put the smaller rear cylinders into the system hoping that the lower pressure would eliminate the problem. Nope...

On the theory that I may have gotten trash in the combo valve, which is SUPPOSED to prevent rear lock-uos, I have ordered another one.
In my testing I have not been able to cause the combo valve to indicate a faulty brake condition (it has a center switch for that purpose.)
I have loosened F or R bleeder screw and pushed the pedal trying to make the poppet move,and it does not.

I plan on upping the rear brakes to the larger shoes/drums, but that requires a different backing plate that is not easily found.
I have read only 1 other post from soneone who went thru the same thing, and changing out the rears finally cured his problem

Somewhere along the line someone has either changed the front brakes and spindles, or they changed the rears.
Dunno..........
What say ye,Chuck??

 

[BlazNT]

Re: MTD Yardman Transaxle Rebuild

My '84 C10 Chevy has a mixture of braking systems.
The VIN indicates that the truck came from the factory with a 4001-5000 GVW brake system, which is the lighter duty setup.
The front has the heavier duty 1.25" rotor and wider caliper, tho the piston bore is the same as the lighter duty 1" rotor.
It also has a double diaphram vacuum booster from the HD system.
The rears are light duty 11x 2 shoes/drum w/1" bore cylinders. (the HD system uses 11.15 x 2.75" shoes/drums, but smaller 15/15" bore cyls.)
I have replaced calipers, drums,rear cylinders, master cylinder (2x) and combination valve.
Bled, rebled, rebled again, and again...........Finally doing a gravity bleed.
Original problems were:
1.pedal mushy.
2.Rear drum brakes locking up.

Gravity bleed finally helped the mushy pedal, but the rear lock-up persists.
I even put the smaller rear cylinders into the system hoping that the lower pressure would eliminate the problem. Nope...

On the theory that I may have gotten trash in the combo valve, which is SUPPOSED to prevent rear lock-uos, I have ordered another one.
In my testing I have not been able to cause the combo valve to indicate a faulty brake condition (it has a center switch for that purpose.)
I have loosened F or R bleeder screw and pushed the pedal trying to make the poppet move,and it does not.

I plan on upping the rear brakes to the larger shoes/drums, but that requires a different backing plate that is not easily found.
I have read only 1 other post from soneone who went thru the same thing, and changing out the rears finally cured his problem

Somewhere along the line someone has either changed the front brakes and spindles, or they changed the rears.
Dunno..........
What say ye,Chuck??

From what you are saying you have too small of brakes in rear. Or too large of a booster/master cylinder. I have seen this a lot in cars and trucks where someone changed the front brakes without finishing the rear. Or your proportioning valve could be the wrong one. Do you know if your proportioning valve is adjustable? If it's not it's probably the factory one which it would make it the wrong one if the front has been changed.

 

[Boobala]

Re: MTD Yardman Transaxle Rebuild

From what you are saying you have too small of brakes in rear. Or too large of a booster/master cylinder. I have seen this a lot in cars and trucks where someone changed the front brakes without finishing the rear. Or your proportioning valve could be the wrong one. Do you know if your proportioning valve is adjustable? If it's not it's probably the factory one which it would make it the wrong one if the front has been changed.

And while you're changing thing's ....... change your panties, .. I smell anchovies !! .. :laughing:..:laughing:

 

[Ronno6]

Re: MTD Yardman Transaxle Rebuild

From what you are saying you have too small of brakes in rear. Or too large of a booster/master cylinder. I have seen this a lot in cars and trucks where someone changed the front brakes without finishing the rear. Or your proportioning valve could be the wrong one. Do you know if your proportioning valve is adjustable? If it's not it's probably the factory one which it would make it the wrong one if the front has been changed.

Makes sense.
I am planning on replacing the prop valve (again) as this one is not acting right..
However, it will probably be similar to the one that is in it.
It is, however, acting just like the original..........

I am planning on putting larger brakes on the rear if the backing plates which I have on the way are the correct ones.

Seems odd that too small rear brakes would lock up,tho.
You are probably correct that the larger booster is over driving them.

BTW, the master cylinder is common to both levels of system.

Boo..........I'm ignoring you!

 

[Boobala]

Re: MTD Yardman Transaxle Rebuild

Makes sense.
I am planning on replacing the prop valve (again) as this one is not acting right..
However, it will probably be similar to the one that is in it.
It is, however, acting just like the original..........

I am planning on putting larger brakes on the rear if the backing plates which I have on the way are the correct ones.

Seems odd that too small rear brakes would lock up,tho.
You are probably correct that the larger booster is over driving them.

Boo..........I'm ignoring you!

 

[Boobala]

Re: MTD Yardman Transaxle Rebuild

Ok, Ok, Ok Ronno....... did a lil research for ya, maybe you can glean a bit of help with this ....

https://techtalk.mpbrakes.com/topic/power-brakes

https://www.speedwaymotors.com/the-toolbox/braking-components-selection-and-design/28678

http://www.hotrod.com/articles/brake-system-fabrication-hot-rod-basics/

http://www.how-to-build-hotrods.com/brake-system.html

 

[Ronno6]

Re: MTD Yardman Transaxle Rebuild

Ok, Ok, Ok Ronno....... did a lil research for ya, maybe you can glean a bit of help with this ....

https://techtalk.mpbrakes.com/topic/power-brakes

https://www.speedwaymotors.com/the-toolbox/braking-components-selection-and-design/28678

http://www.hotrod.com/articles/brake-system-fabrication-hot-rod-basics/

http://www.how-to-build-hotrods.com/brake-system.html

Geez, thanks,Boo!
I take back HALF of everything bad I've said about you!

 

[Ronno6]

Re: MTD Yardman Transaxle Rebuild

And while you're changing thing's ....... change your panties, .. I smell anchovies !! .. :laughing:..:laughing:

I wondered who that was sniffing around my "junk."

 

[Boobala]

Re: MTD Yardman Transaxle Rebuild

I wondered who that was sniffing around my "junk."

Most definitely it twas NOT I, I'm in another part of the world ! .. :laughing:..:laughing: