[Greywolf]

PART 1

"It was a dark and stormy night" (honestly - we've been getting a lot of rain in Memphis this summer) so I went out to the shop to see if I could figure out why the brakes on my Craftsman weren't doing any good.

You could step on them going up a hill to let the tractor roll back down - which was kind of handy a few times! I began to wonder if, suppose I were to build a tractor for the lawn mower races, could I seperate the clutch and brake for gear changes. But it wasn't good for emergency stopping situations.

The first step was to go look around the bottom of the frame and spot the linkage. The pedal is on the left, push-rod is on the right, and the brake itself is mounted on the transaxle case just in front of the right rear axle stub.

(Technically, it is a mechanical disc brake, which I thought was a strange mix of old and new technology)

BY THE WAY: We're talking about an obscure tractor to find parts for here. It's a 917-258542 and I had to go through a two-step process to find what I needed for it. You'll see that as we go along here.

The push rod acts on a lever that has a cam shaped into it. The cam pushes on two dowel pins that press the outer brake pad against a disk that is on a shaft on the side of the transaxle.

That disk is supposed to be able to slide in and out on splines on the brake shaft. Behind the disc is another brake pad.

ALL OF THE ABOVE were rusted STUCK, because the owner before me parked it outdoors unprotected... The cam lever was stuck in the park position, and the brake connecting rod wasn't even making contact with it. Because of that - the pads were completely shot since the tractor had been driven anyway!

On top of that, the brake disk itself was rusted fast and had to be soaked with break-free and carefully worked loose...

("Watson? I believe we now have all of our facts...")

One of the first problems was to remove the brake unit. I saturated everything with PB Blaster, but I know that if PB doesn't do it there is an even better stuff you can make at home: Mix one part acetone to one part transmission fluid. The acetone helps the tranny fluid to wick into stuck stuff, and the tranny fluid breaks down crud!

I still snapped a bolt, and am working on it slowly so that I don't have to drill it out and put in a helicoil. One tactic I'm using is to heat it with a propane torch and then CHILL it quickly so that the metals expand and contract, but for now I'm letting it soak.

The brake "CALIPER" assembly is an aluminum block held on by two 1/4 X 20 bolts with a stud for the lever. The two dowels that act on the brake pads had to be driven out with a drift punch (use a deepwell socket to back up the assembly and give the pins somewhere to go). There is also a rectangular metal plate that you must not lose because it keeps the dowels from ruining the back of the outer brake pad. The cam lever also has a spring that pushes it out on its shaft that you don't want to lose.

The best way to keep all these parts together is to immediately bag everything into ziplocks. I use two - One for nasty parts, and one for parts that have been cleaned up. Everything rusted on this project has been cleaned up (including bolt HEADS) mainly on a bench grinder using the wire wheel, and also with various hand tools. "Anything nasty and cruddy will work nasty and cruddy" so I never put anything back together that is dirty!

The cam lever will be painted, and the choice lubricant in my opinion is white lithium grease, because it won't break down or wash away.

Now for the confusing part:

SEARSPARTSDIRECT has ZERO information about this one, even though I found the exact parts breakdown illustration on their website. The transaxle is discontinued and that is what the brake is part of. I messed around for hours online before I hit on the answer.

All of the parts for this comedy of errors are now supplied by Tecumseh. The tractor is a Craftsman product, the transaxle was made by Peerless, and it seems they handed everything off once the model run was over...

If you go to http://PartsandService.ca you can find a breakdown that DOES show parts that you can order. The result is a Tecumseh part number that works at almost every other site. Glenn M also posted a link to get the transaxle manual from: http://search.cartserver.com/search...ory=Tecumseh_Parts&maxhits=50&keywords=740045

*Glenn M: You are THE MAN!!! :thanku:

It costs a mere eleven bucks, roughly.

There are many parts websites, and I hope MTF gains one or more of them as sponsors here so us little tractor guys have resources that also help keep MTF going...

In PART 2 I'm going to post up all of the pictures of this project so that everything is clearly shown and simple to understand. It will be in this same thread farther along.

~Greywolf
(AKA: Dutch J. USN/Ret'd)

PS: The pads for mine turned out to be Tecumseh part# 799021 and a pack of 2 is only about five bucks. You should look up what your own are if the model number is at all different just to be sure you have the right ones

ADDITIONAL NOTES:
MAIN Tecumseh Homepage

Tecumseh Engines

Tecumseh Engine Recall alert

 

[jeepersmitty]

Looks like you have it under control. Will be waiting for pics in part II.

 

[Greywolf]

'Reason I got this far is in part because I stopped in here...

 

[Fcubman]

Another Holmes fan - now we have two things in common, the MTF and Sherlock.
I liked "The Red-headed League", very clever of John Clay.

 

[Greywolf]

Update: Brake Pads came, they turned out to be individual packs of one each - good thing I ordered two of them to be sure.

They are actually made by "Stens" ( www.stens.com ) part# 240-366 which crosses to Tecumseh/799021

I'll be spending some quality shop time, and will check the fit first of all.

They look like a better pad than the original. From what I see looking at them they are a metallic impregnated compound similar to better types of disc brake pads for automobiles and trucks. The originals looked like plain old hard plastic or something.

 

[Greywolf]

(Copy the diagram while you can - it's an attachment)
(IE: STEAL THIS PICTURE!!! You'll be glad you have it later)

For discussion purposes - I grabbed an exploded view of a standard Peerless Transaxle as used in 917-XXXX... series riders and sanitized it of extra detail, then added my own index numbers. This image is helpful for remembering where all of the goodies go. (the numbers are also NOT smeared looking)

The Trim Strip shown is probably not needed, and is in the way when inspecting and lubricating the dowel pins and cam lever.

As explained above - typically a lot of the parts shown can rust and get stuck. The dowel pins that press the outer brake pad against the brake disc are notorious for getting frozen in place by corrosion. Every moving part you see should be sprayed periodically with break-free or PB Blaster, whatever your favorite flavor is.

I assembled everything with white lithium grease because I know it lasts until heck freezes over or Clinton confesses - whichever comes last

I have another diagram on the way that should help in explaining how to adjust it. Not shown in this one for some reason was the Cam Lever Tension Spring. The linkage is much better shown in the diagram to follow this one.

Fire off any questions you have!

*NOTE: Part #8 is an unusual length - a piece of 1/4-20 threaded rod (allthread) can be used instead, and suitable nuts used on it.
*NOTE 2: The pads fit perfectly.
*NOTE 3: Click on diagram for a larger, more clear image.

 

[Tractor-Holic]

Anybody but me ever use a hole saw to carve out "pucks" for lawn tractors with disc brakes??...I've bought some new car or truck disc pads at flea markets for a buck or two (often the box gets lost or people dont know what they fit,etc)..I buy the riveted ones and drill out the rivets,then use the correct hole saw to cut out a "slug" the right size to fit the tractor,and file them down a bit if they are too thick..

Yeah,I go to great lengths to avoid ordering the correct parts,unless I know they are readily available and cheep--most of the tractors I fool with are "obsolete" and unless you MAKE parts yourself,your boned!..glad in your case you can still get the right parts...I'm usually forced to "invent" something or modify something similar till it works to get them useable..

 

[SockPuppet]

Anybody but me ever use a hole saw to carve out "pucks" for lawn tractors with disc brakes??...I've bought some new car or truck disc pads at flea markets for a buck or two (often the box gets lost or people dont know what they fit,etc)..I buy the riveted ones and drill out the rivets,then use the correct hole saw to cut out a "slug" the right size to fit the tractor,and file them down a bit if they are too thick..

Yeah,I go to great lengths to avoid ordering the correct parts,unless I know they are readily available and cheep--most of the tractors I fool with are "obsolete" and unless you MAKE parts yourself,your boned!..glad in your case you can still get the right parts...I'm usually forced to "invent" something or modify something similar till it works to get them useable..

I do basically the same. I've made new pads for my LT4000 that are identical to the ones pictured above.

The only thing I would add is that you have to be particularly careful with the dust.

 

[Greywolf]

In recent years, they go to some lengths to avoid using asbestos to make any kind of brake liner (you have to figure it gets shed by vehicles going down the road too). But what that IS - I just don't know. It probably isn't very good to breath either.

I thought about cutting up old pads, and I ought to measure them to establish what the actual dimensions are - especially THICKNESS when new.

I set mine so that they don't slam the tractor to a skidding halt because I'm betting that it puts a lot of wear on the transaxle internals. But it (the tractor) can't be pushed when the parking brake is on...

I also have high-lug tires, and skidding them is not something I want to do with increased traction on dirt.

To adjust them, I put it in park and adjusted the linkage until it held solidly. I also wanted the brakes to be disengaged when shifting on the fly - so there would be less wear on them normally. THAT becomes a matter of personal preference....

The spring on the link rod allows a varied amount of pressure to be applied, instead of an "ALL ON-ALL OFF" effect, and that's pretty important. It doesn't take much movement to engage them. That spring must always be on the adjustment nut side of the cam lever.

Initially - you want the adjuster nut and it's lockdown nut as far to the front of the tractor on the link rod as they'll go. If the threads are kind of rusty, you can run a die down them or spray them good with lock fluid, break free, etc...

Start from all the way forward anyway, and adjust them with the tractor in park. Then release the brakes and see what kind of clearance you have.

Test riding it will reveal a happy medium, but you don't want the brakes engaging hard while shifting.