Brakes on 1855. something aint right?

bison

Well-known Member
I am rebuilding an 1855.
I done the reared and transmission and am now in the process of putting the brakes together.
You can see in the pics that the brake piston had been riding against the bull pinion(with brake applied) but even with new brake discs there is only 1/16 clearance left between a fully retracted brake piston and the pinion with all brake parts in place
What am I missing here?
mvphoto29474.jpg


mvphoto29476.jpg
 
Was there supposed to be thin shims in there between the cover and housing or was that just some of the late ones with a mechanical actuator?
 
Did someone machine the outer or separator plates too thin? That is about all it could be. I see the piece of fiber glued to the piston, so that isn't it. I would compare parts with the other side.
 
(quoted from post at 17:36:01 01/10/19) Did someone machine the outer or separator plates too thin? That is about all it could be. I see the piece of fiber glued to the piston, so that isn't it. I would compare parts with the other side.
oth sides are identical in measurements.
Regardless of the internal brake parts is the fact that the brake pistons have a maximal travel of only 3/16' from all the way retracted till it bottoms out against the bull pinion. 1/16th of that travel is the necessary brake disc release clearance, which leaves only 1/8" to wear away on the discs before the piston hits the pinion,...which is not very much IMO.

Thicker brake discs would not fit as there is no room for it
New discs are just a wee bit over 1/2' thick.
 
did brakes on my Truck and although the pistons were retracted as far as
they would go, they couldn't go all the way...new calipers were required.
I know this isn't the same, but something that old could be doing
something similar. If not I'd say wrong parts, these things can't be
complicated and loose is how I'd expect them to be.
 
I have not done one of these for a long time! I suggest that you go to agcopartsbook online and look up the 1855. Page 113 items 28 and 34. Maybe someone else has miss matched these parts? Could change how many shims are under the housing.
 
(quoted from post at 20:44:23 01/10/19) I have not done one of these for a long time! I suggest that you go to agcopartsbook online and look up the 1855. Page 113 items 28 and 34. Maybe someone else has miss matched these parts? Could change how many shims are under the housing.
have owned this tractor for 32 years and nothing has ever been done to the brakes.
parts #'s are identical to what is listed in my 1855 parts book and I got the new springs and discs from AGCO

Yes shim packs behind the brake/pinion housing will affect pinion to brake piston distance but that cannot be altered as the shim packs control differential/bull pinion end play.
 
That's good that you know that no one else has been into it. Just curious does the parts book you have show two different inner bearings depending on serial number of your tractor. Maybe it got miss matched on the assembly line if it was close to the serial number break. From the picture on the net I am not sure were part 34 goes? Looks like some kind of spacer. I know what you mean about the shims under the housing as they are how you set the preload on the ring gear carrier. But different bearing sets may have a different overall thickness. A thicker bearing set would require more shims and give you more clearance. I have seen brake disc so worn that the piston came out of the bore enough to let the oring leak. But I don't remember if it had rubbed on the bull pinion. Question, If you place a straight edge over the brake housing and measure the distance to the bull pinion. Is it the same on both sides of the transmission? Just trying to help.
 
Have you removed the piston from the housing? I had one that the stem for the parking brake part of the piston broke, although everything was still in tacked and not leaking, it created a situation like what you have by increasing the overall length/height of the piston
 
# 34 is an fiber insulator that goes between the brake disc and the adjuster plate.
The 0 rings in the piston housings have been replaced and everything looks fine in there.
Bull pinion face to end of housing distance are within a couple thou of each other.
Differential carrier and crown/pinion backlash have been reset to factory specs which required removal of 1 shim each side.

AFAIAC the only way to increase piston travel is to machine the face of the piston back a bit where it contacts the bull gear but there ain't enough meat Imo to do that safely without risking piston integrity.

I'm at a loss.
 
# 34 is an fiber insulator that goes between the brake disc and the adjuster plate.
The 0 rings in the piston housings have been replaced and everything looks fine in there.
Bull pinion face to end of housing distance are within a couple thou of each other.
Differential carrier and crown/pinion backlash have been reset to factory specs which required removal of 1 shim each side.

AFAIAC the only way to increase piston travel is to machine the face of the piston back a bit where it contacts the bull gear but there ain't enough meat Imo to do that safely without risking piston integrity.

I'm at a loss.
 
So are both pistons hitting the bull pinions? I must be looking at a different parts diagram than you. Part #10 is the friction disc bonded to the piston in the drawing I am looking at. I have tried to load the drawing I have and it won't load. It is at agcopartsbooks.com. I would sure like to help! 8zero1-55four-68eight6 Dennis
 
(quoted from post at 15:04:30 01/11/19) So are both pistons hitting the bull pinions? I must be looking at a different parts diagram than you. Part #10 is the friction disc bonded to the piston in the drawing I am looking at. I have tried to load the drawing I have and it won't load. It is at agcopartsbooks.com. I would sure like to help! 8zero1-55four-68eight6 Dennis

Yep, both piston were hitting the pinions but new brake discs solved the problem for now.
The as you call it.. the friction discs.. are in my case not bonded to the pistons. as for the part # I relied on the # Tractorderic posted but it could be #10,..I did not verify.

All the part #'s on the pinion,brake housing, brake parts and cover are the same as listed in the 1855 parts book I have.
 
(quoted from post at 16:25:06 01/11/19)
(quoted from post at 15:04:30 01/11/19) So are both pistons hitting the bull pinions? I must be looking at a different parts diagram than you. Part #10 is the friction disc bonded to the piston in the drawing I am looking at. I have tried to load the drawing I have and it won't load. It is at agcopartsbooks.com. I would sure like to help! 8zero1-55four-68eight6 Dennis

Yep, both piston were hitting the pinions but new brake discs solved the problem for now.
The as you call it.. the friction discs.. are in my case not bonded to the pistons. as for the part # I relied on the # Tractorderic posted but it could be #10,..I did not verify.

All the part #'s on the pinion,brake housing, brake parts and cover are the same as listed in the 1855 parts book I have.

Pretty sure you must have this information already, but it only takes a second to post, so if you don't, here are some spec's from my manual: Piston thickness 2-9/32",
adjusting plate thickness 0.589-0.599, 1755-1855 are the same, and have travel listed as 0.024 - 0.035.
In the assembly of the brake , "install separator plate with taper on separator inward". Does not give the thickness of the separator plate. The insulator plate on the piston is just supposed to bonded with Permatex in two places (180 apart) to retain its position.
 
(quoted from post at 07:14:16 01/12/19)
(quoted from post at 16:25:06 01/11/19)
(quoted from post at 15:04:30 01/11/19) So are both pistons hitting the bull pinions? I must be looking at a different parts diagram than you. Part #10 is the friction disc bonded to the piston in the drawing I am looking at. I have tried to load the drawing I have and it won't load. It is at agcopartsbooks.com. I would sure like to help! 8zero1-55four-68eight6 Dennis

Yep, both piston were hitting the pinions but new brake discs solved the problem for now.
The as you call it.. the friction discs.. are in my case not bonded to the pistons. as for the part # I relied on the # Tractorderic posted but it could be #10,..I did not verify.

All the part #'s on the pinion,brake housing, brake parts and cover are the same as listed in the 1855 parts book I have.

Pretty sure you must have this information already, but it only takes a second to post, so if you don't, here are some spec's from my manual: Piston thickness 2-9/32",
adjusting plate thickness 0.589-0.599, 1755-1855 are the same, and have travel listed as 0.024 - 0.035.
In the assembly of the brake , "install separator plate with taper on separator inward". Does not give the thickness of the separator plate. The insulator plate on the piston is just supposed to bonded with Permatex in two places (180 apart) to retain its position.
hanks for the info.
My ITC repair manual does not mention anything about piston/adjusting plate dimensions or travel nor about bonding of the insulator to the piston.
 
(quoted from post at 10:25:09 01/12/19)
(quoted from post at 07:14:16 01/12/19)
(quoted from post at 16:25:06 01/11/19)
(quoted from post at 15:04:30 01/11/19) So are both pistons hitting the bull pinions? I must be looking at a different parts diagram than you. Part #10 is the friction disc bonded to the piston in the drawing I am looking at. I have tried to load the drawing I have and it won't load. It is at agcopartsbooks.com. I would sure like to help! 8zero1-55four-68eight6 Dennis

Yep, both piston were hitting the pinions but new brake discs solved the problem for now.
The as you call it.. the friction discs.. are in my case not bonded to the pistons. as for the part # I relied on the # Tractorderic posted but it could be #10,..I did not verify.

All the part #'s on the pinion,brake housing, brake parts and cover are the same as listed in the 1855 parts book I have.

Pretty sure you must have this information already, but it only takes a second to post, so if you don't, here are some spec's from my manual: Piston thickness 2-9/32",
adjusting plate thickness 0.589-0.599, 1755-1855 are the same, and have travel listed as 0.024 - 0.035.
In the assembly of the brake , "install separator plate with taper on separator inward". Does not give the thickness of the separator plate. The insulator plate on the piston is just supposed to bonded with Permatex in two places (180 apart) to retain its position.
hanks for the info.
My ITC repair manual does not mention anything about piston/adjusting plate dimensions or travel nor about bonding of the insulator to the piston.

I have had my 1955, and a neighbors 2-105 apart, granted they are triple disc, but it seems to me that the adjuster plate was extended out further, not recessed as much in the housing as your picture depicts. I tried to find a dimension from the inner most disc wear area to the housing external face, (cover bolt surface), but I cannot find this anywhere. IMO it has to be the total thickness that is short, disc's, separator and adjuster. The insulator disc is a non-wear item. I could not find a thickness on the disc's either.
 
The pic shows the brake parts including the adjuster plate installed in the housing without the springs behind it( for measuring purpose), with springs installed the adjuster plate is protruding past the face of the housing.
Combined wear in housing and separator and adjuster plate is as far as I can determine it is less than 1/16"
 
(quoted from post at 12:03:53 01/12/19) The pic shows the brake parts including the adjuster plate installed in the housing without the springs behind it( for measuring purpose), with springs installed the adjuster plate is protruding past the face of the housing.
Combined wear in housing and separator and adjuster plate is as far as I can determine it is less than 1/16"

This was like this when you took it apart, correct? I see in your post you were in the rear end, but since that time, you have not used it, correct? Did you have the support housings off, or better yet, did anyone before you have them off? Are the shims between the main case and the support housings the same as it was from factory? They are very stringent on this in the manual, so as not to change that dimension. When you think about this, it can only be that the housing shim to main frame was messed with, and does not have the correct install relationship to the shaft end, or the inner disc has worn away material from the housing. I would check dimensions of all of your new wear parts, if after market. If the are, maybe someone you know can give those dimensions from factory parts, you just never know.
 
Yes it was like that when I tore into it and no I have not used it since. The tractor is getting a major overhaul front to back top to bottom. I am the first one to get into the tranny/rear end since it came out of factory..I had the transmission, crown and pinion ,bull pinions and bull gears and the PTO unit all apart
I replaced the crown and pinion and the 6 side gears.The bull pinions i swapped from side to side and the bull gears are turned around.
I reset the differential end play and pinion backlash as per manual and as indicated on the crown. Shim packs are the same each side as before but I removed one thin shim from each side to get the correct side play.
The old bull pinion bearings went back in but the pinion driving the crown got new bearings.

As for the brake wear parts, it does not matter at this point If the piston only has 3/16' travel from fully retracted to hitting the bull pinion when every part would be renewed there would still be only 3/16' of travel and that can't be changed unless I grind the bull pinions shorter or machine the piston faces deeper,...neither one I feel like doing.
 
(quoted from post at 16:23:12 01/12/19) Yes it was like that when I tore into it and no I have not used it since. The tractor is getting a major overhaul front to back top to bottom. I am the first one to get into the tranny/rear end since it came out of factory..I had the transmission, crown and pinion ,bull pinions and bull gears and the PTO unit all apart
I replaced the crown and pinion and the 6 side gears.The bull pinions i swapped from side to side and the bull gears are turned around.
I reset the differential end play and pinion backlash as per manual and as indicated on the crown. Shim packs are the same each side as before but I removed one thin shim from each side to get the correct side play.
The old bull pinion bearings went back in but the pinion driving the crown got new bearings.

As for the brake wear parts, it does not matter at this point If the piston only has 3/16' travel from fully retracted to hitting the bull pinion when every part would be renewed there would still be only 3/16' of travel and that can't be changed unless I grind the bull pinions shorter or machine the piston faces deeper,...neither one I feel like doing.

I seriously doubt it came from factory with this issue. Something wore and failed which allowed the shaft to move outward, or someone had it apart. On the inside you have a thrust washer, thrust bearing and support bearing. The pinion shaft is retained in position between the outer bearing and the thrust bearing at the differential. The outer bearing is the one item that keeps the shaft from working out to toward the brake piston. Is it possible, that someone had this housing off, and replaced the outer bearing? There are different bearings for different housings. For example,if you look at the two (2) Timkin's that are listed, the inner bore for the race are the same, but the width is .625 different. The outer match to this race, has a larger outer bore, so it would not work. (cad drawings for Timken are online) Is it "possible" that someone did not notice this in this tractors previous life and mismatched a bearing and race? Milling the brake piston or grinding the shaft does not seem like it going to fix the root cause, and IMO it will show up some day.
 
(quoted from post at 07:40:04 01/13/19)
(quoted from post at 16:23:12 01/12/19) Yes it was like that when I tore into it and no I have not used it since. The tractor is getting a major overhaul front to back top to bottom. I am the first one to get into the tranny/rear end since it came out of factory..I had the transmission, crown and pinion ,bull pinions and bull gears and the PTO unit all apart
I replaced the crown and pinion and the 6 side gears.The bull pinions i swapped from side to side and the bull gears are turned around.
I reset the differential end play and pinion backlash as per manual and as indicated on the crown. Shim packs are the same each side as before but I removed one thin shim from each side to get the correct side play.
The old bull pinion bearings went back in but the pinion driving the crown got new bearings.

As for the brake wear parts, it does not matter at this point If the piston only has 3/16' travel from fully retracted to hitting the bull pinion when every part would be renewed there would still be only 3/16' of travel and that can't be changed unless I grind the bull pinions shorter or machine the piston faces deeper,...neither one I feel like doing.

I seriously doubt it came from factory with this issue. Something wore and failed which allowed the shaft to move outward, or someone had it apart. On the inside you have a thrust washer, thrust bearing and support bearing. The pinion shaft is retained in position between the outer bearing and the thrust bearing at the differential. The outer bearing is the one item that keeps the shaft from working out to toward the brake piston. Is it possible, that someone had this housing off, and replaced the outer bearing? There are different bearings for different housings. For example,if you look at the two (2) Timkin's that are listed, the inner bore for the race are the same, but the width is .625 different. The outer match to this race, has a larger outer bore, so it would not work. (cad drawings for Timken are online) Is it "possible" that someone did not notice this in this tractors previous life and mismatched a bearing and race? Milling the brake piston or grinding the shaft does not seem like it going to fix the root cause, and IMO it will show up some day.


AFAIAC this setup is all factory,..been running like this for 45 years/7000 hrs, never had an issue,..Just had poor brakes for years. nobody been in it but me since it came off the assembly line.nothing appears mis matched, all parts are installed and adjusted correctly.

Would be nice to know what other 1855's measure between brake housing face and end of pinion.
 
(quoted from post at 11:02:33 01/13/19)
(quoted from post at 07:40:04 01/13/19)
(quoted from post at 16:23:12 01/12/19) Yes it was like that when I tore into it and no I have not used it since. The tractor is getting a major overhaul front to back top to bottom. I am the first one to get into the tranny/rear end since it came out of factory..I had the transmission, crown and pinion ,bull pinions and bull gears and the PTO unit all apart
I replaced the crown and pinion and the 6 side gears.The bull pinions i swapped from side to side and the bull gears are turned around.
I reset the differential end play and pinion backlash as per manual and as indicated on the crown. Shim packs are the same each side as before but I removed one thin shim from each side to get the correct side play.
The old bull pinion bearings went back in but the pinion driving the crown got new bearings.

As for the brake wear parts, it does not matter at this point If the piston only has 3/16' travel from fully retracted to hitting the bull pinion when every part would be renewed there would still be only 3/16' of travel and that can't be changed unless I grind the bull pinions shorter or machine the piston faces deeper,...neither one I feel like doing.

I seriously doubt it came from factory with this issue. Something wore and failed which allowed the shaft to move outward, or someone had it apart. On the inside you have a thrust washer, thrust bearing and support bearing. The pinion shaft is retained in position between the outer bearing and the thrust bearing at the differential. The outer bearing is the one item that keeps the shaft from working out to toward the brake piston. Is it possible, that someone had this housing off, and replaced the outer bearing? There are different bearings for different housings. For example,if you look at the two (2) Timkin's that are listed, the inner bore for the race are the same, but the width is .625 different. The outer match to this race, has a larger outer bore, so it would not work. (cad drawings for Timken are online) Is it "possible" that someone did not notice this in this tractors previous life and mismatched a bearing and race? Milling the brake piston or grinding the shaft does not seem like it going to fix the root cause, and IMO it will show up some day.


AFAIAC this setup is all factory,..been running like this for 45 years/7000 hrs, never had an issue,..Just had poor brakes for years. nobody been in it but me since it came off the assembly line.nothing appears mis matched, all parts are installed and adjusted correctly.

Would be nice to know what other 1855's measure between brake housing face and end of pinion.


Curious as to what you ever found or did to remedy this issue? Were you ever able to find that measurement?
 
Nope. I bolted it to together the way it was.
I just have to check more often how much the discs wear with use.
Maybe it wears much less than I think it will.
 
quote="bison"](reply to post at 16:27:28 02/04/19) [/quote]
Not sure if it was possible, but could the tractor have been assembled with 1955 bull pinions? They have longer splines for the triple disc brakes, been too long since I was close to either tractor, splines only need to extend slightly beyond the hub of the brake discs. hope you find a solution.
 

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