C-4 Schematic changing brake linings

Hi, I am restoring a 1404 and was thinking of replacing the brake lining, anyone ever attempt this and does anyone have a parts souce and schematic for this mechanical marvel??

Only drove the machine for a few hours before teardown, but it seemed to take allot pressure to operate the stearing brakes. Thanks in advance for your help.

John

A couple of questions before I try to reply.

1. Did both sides require the same amount of pressure when pulling back to brake or steer the machine?

3. When pulling back on the levers do they pull back and stop evenly? Does one side seem to creep and not stop?

2. Did you have a complete fill on the hydraulic fluid for steering and braking?

hi, yes as I remember they were both pretty even, it did take allot more effort to turn in the lower gears though.
The fluids appeared to be both the same.
would just like the reassurance that everything is A-ok before putting machine back in service.
I am also curious to see a schematic just to see how everthing works in there

Thankyou!
John

I have a schematic for you. PM me and I will send you everything I have. Its about ten pages.

More to follow.

Still more.

The meat.

More

Last page is too big. Over the forums limit. PM me and send me your email address. The last page is an exploded view of the C-4. The shifting linkage is the only diffrence. Also do you have or know of another C-4? I am need of a working unit or a broken one.

Also PM and email member BYOUNG (he doesnt visit the forum much during the summer). I believe he just rebuilt his C-4. He would be a valuable source of information.

Teeoster said:

hi, yes as I remember they were both pretty even, it did take allot more effort to turn in the lower gears though.
The fluids appeared to be both the same.
would just like the reassurance that everything is A-ok before putting machine back in service.
I am also curious to see a schematic just to see how everthing works in there

Thankyou!
John

Click to expand...

With the OC4 you need to plan your turns as it does not respond quickly. It is just the nature of the machine. Your turns are best accomplished by not locking down the lever but by pulling it back multiple times and maintaining power when turning. The turns will be quicker as your speed and rpm rise. The OC4 in the standard Imp chassis and engine configuration is quite durable. Adding more hp may be a problem. Make sure your brake cylinders and slave cylinders are all working properly and rear band are adjusted properly at the rear end so your steering levers do not bottom out. Bleed the lines and recheck steering effort.

Have you drained the rear end and checked the oil for any contaiments?
What oil do you run in the rear end? On a C-4 or OC-12 there have been different oils recommended - even from the factories. The most common is hydraulic oil preferably 10W if used in winter conditions. Cats used for other purposes in other seasons should adjust accordingly. I use Aeroshell 100 Mineral or Unocal HT-4 which is a 10W Hydraulic Tractor fluid. Don't use heavy gear oil or you will have difficulty steering.

The OC12 used in later models is much more positive in operation but would be a major job to retrofit in the Imp.

Do you know how many hours are on the machine? Was it used to pull a trail drag or plow snow? This is important to brake band wear and life.

You maybe able to get an Imp manuel from Peterson Equipment in Logan UT by calling them and giving them your model and serial number. The phone number is 435-752-5110.

I may be able to borrow a manuel from a neighbor that purchased my restored 1974 Imp and have it copied if you can not locate one.

Bill

Teeoster, pull the rear cover and look at the material on the upper part of the brake band. I have found that these OC-4's usually wear the wet brake lining out at a point 3 or 4 inches from the ends first. If that looks good ( should be about a 1/4" thick) look at adjusting the bands in the same location by pulling the cotter pin and clevis pin and giving the adjusting bolts a couple of turns. I know this sounds complicated but is really straight forward once you pull the rear cover and look at it. If your linings are shot remove the same adjustment pins and roll the bands out (WEAR GLOVES) and have them re-lined with wet brake material. Feed a little rope around the differential gears and tie it to the bands to pull on to aid in reinstallation. Do NOT use gear lube, change brake fluid yearly, and if kept in adjustment you will be very pleased with your OC-4.

One more thing. If the lining material on your brake bands is worn out and you continue to tighten the external adjustments and "pump it up" with the steering levers you might ruin the bands themselves. What happens is the ends of the bands start butting up against each other. Pull the cover and have a look.

Thanks, That sounds like a good start, Looking to see what is actually going on is probably the best place to start, I got a feeling that everything is just fine, Replacing fluid and adjusting the bands will probably make everything happy again

If you get a chance check out my last post under the "IMP 1402 conversion" thread

Thanks John

Gang,

I finally got around to the transaxle, and found it to be filled with Gear Lube! Brake bands looked great; in fact the whole unit looked great on the inside. I'm sure the steering effort will be greatly reduced when I fill her up with some 10 or 15 wt hydraulic oil. Still would consider a OC-12 swap if anyone comes across one for sale???

Thanks for your help, and the schematics are already printed and put in my repair manual. Will ve start a new post soon to show the complete restoration project going on here in Michigan.

One more thing does anyone know the proper interneal adjustment for the brake bands? Manual only says to adjust brake bands, but doesn't say how?

Thanks!

Start by completely loosening the external adjustment nuts on the allthread rod that passes through the actuating levers. Move to the inside where the end of the bands have a looped end through which a clevis pin attaches them to adjustment bolts. Pull the pin, take up some slack with the bolt, replace the pin and secure it with a cotter pin. Get them as tight as you can by hand and then do fine adjustment externally. If the external actuating levers are too far forward, take up more slack at the band adjustment. As the bands wear you can make external adjustments up to the point where the actuating levers start pushing down on the allthread that pulls them. Then pull the back cover and tighten the bands again. By the way, I have good results using regular old 10W30 motor oil and changing it frequently to keep the wear particals flushed out. Works good in cold, high altitude snow. Hope this helps.

Hello,
In my OC-4 I ran the Unical 10Wt oil for a short time. After talking to Peterson's about it, they really discouraged me from using it. They felt it was too light and would cause premature wear. I was told that Thiokol ran strait 50 wt minerial oil for years. Aeroshell 100 works really well. (same stuff)
The most important thing is to keep the adjustments on the band up so there isn't a lot of slop and make sure you don't have any air in your hydrolic lines.
That is typically the problem with the OC-4 steering.

Thanks Guys

Nutsster, did you mention that you had a V-6 in your 1402? I am in the middle of fitting up a Ford 2.8 liter to my 1404 and it bolted up to everything just perfect: Except it is super tight on the front end. Water pump pully comes within 3" of the front of the machine...No room for the radiator even with no fan at all. I'm think about moving the engine and trans back 3" to make some room, but as you can imagine it creats lots of other problems. Just wondering if you might have any pictures of the engine install on yours without the cowling in place??

well if you read the manual it reads to us a 50wt above 20 degrees and dn 600 below after talking with oil companys they found a cross reference for dn600 to be 10w30 mtr oil. the problem that i have found with thicker oil is the brake bands drag and don,t release as well. also if you look at a oc4 the oil has to pass through the bearings to feed transmission so if you run thick oil the the front in put bearing dosen.t get oil. when you fill with oil fill to plug and put side plug back in an add two more quarts of oil this will put more oil on bands.i have been running synthec 10/30 in oc4 oc12 and oc 15 rearend for years

Thanks for clearing up the oil type to use. I did find that using synthetic motor oil in my dirt bikes and 4 whelers presented a big problem. Because the clutch runs in the same oil as the engine, it would slip really bad when I used synthetic motor oil. It seems that the oil is so "slippery" that the clutch was rendered useless by it. Turns out that this a well known problem

Just wondering if the brake bands may have the same reation to the synthetic motor oil?? Do you think it would be ok to run regular high grade 10w30?

One more question, where would be a good place to find gasket material big enough to make a new one for the rear cover?

The 90wt gear lube is roughly equivelent to 50wt motor oil. Some of the additives used in gear lube have a bad effect on the bronze bushings used in these drives. If you want to use what Clark recomends use non-detergent 30wt motor oil for 20 degrees temperature. I use 10w30 from Walmart and change itat least twice a season to keep it flushed out. Change it after the machine has been running and is hot, just like you would your motor oil. Once you see how much metalic particals drains out with the old oil you too will be a believer in frequent changes. I think Nutsster is right about bleeding lines. Brake fluid attracts moisture so flush it through with new stuff every season too.