Thomas Backhoe

[Wm McNett]

Thank you so much. I've been reading the repair manual for hours and I've filled in many of the blanks about these valves. There are a few differences though... the repair manual in the link shows spool wipers that are held in place by a retaining clip and two screws. There are no such items on my valves. Also... the manual show spacers between the valve sections at the point where the long shaft passes through the valves (at the point where the “Load Check” valve is secured by the shaft). There were no spacers between my valve sections but the seal kit that I purchased years ago does have the spacers included along with the 4 “O” rings that seal each valve to the next. I don't know if I should use the spacers or not but I can tell you this.... they are very very thin, only .003” (three thousandths) thick.

bTw... I soaked the cast valve bodies overnight in a degreaser I bought at Auto Barn and take a look at what the stuff did...

That's the best paint remover I've ever used. All it took was a light wipe with a wire brush... no real pressure... and the cast valve body shined almost like new.

Your welcome. I was excited to find someone working on a Kontak valve. Mine isn't leaking nore does it have a bunch of rust but the hoe was lacking power which started my search for information.
I noticed yours has a few either service port relief valves or anticavitation valves. My guess, looking at the pictures, is direct acting relief valves. I hope your parts cleaner/paint stripper didn't eat the o-rings on them.
Heres another manual
http://www.hypneu.de/cms/fileadmin/...il/MCD/Catalogs/GENERAL/Mobca_Uk/_4-2KA18.pdf

don't know why my above post wouldn't post correctly, glad to see someone fixed it, perhaps it had to do with using Mozilla Firefox on this 10 year old laptop but Internet Explorer seems to work just fine

 

[Jyuma]

Your welcome. I was excited to find someone working on a Kontak valve. Mine isn't leaking nore does it have a bunch of rust but the hoe was lacking power which started my search for information.
I noticed yours has a few either service port relief valves or anticavitation valves. My guess, looking at the pictures, is direct acting relief valves. I hope your parts cleaner/paint stripper didn't eat the o-rings on them.
Heres another manual
http://www.hypneu.de/cms/fileadmin/download/downloads/Parker/Hydraulik/Mobilhydraulik/CD_mobil/MCD/Catalogs/GENERAL/Mobca_Uk/_4-2KA18.pdf

don't know why my above post wouldn't post correctly, glad to see someone fixed it, perhaps it had to do with using Mozilla Firefox on this 10 year old laptop but Internet Explorer seems to work just fine

Almost ready for paint...

With the possible exception of the pressure release valve (or whatever it is) located on the top of valve one, everything else looks to be in near perfect condition. New seals and a fresh coat of paint and this valves assembly rebuild should be history (I hope).

In the close-up view below, notice the valve sequence #'s stamped into the casting just under the lower working ports. I used a steel stamping set to number the valves before disassembly. I didn't want to risk messing up the order.
(Yes, I know... I stamped the #3 upside-down. hahaha)

 

[Tazza]

Almost ready for paint...

With the possible exception of the pressure release valve (or whatever it is) located on the top of valve one, everything else looks to be in near perfect condition. New seals and a fresh coat of paint and this valves assembly rebuild should be history (I hope).



In the close-up view below, notice the valve sequence #'s stamped into the casting just under the lower working ports. I used a steel stamping set to number the valves before disassembly. I didn't want to risk messing up the order.
(Yes, I know... I stamped the #3 upside-down. hahaha)

I really hope this is the last time you have to have it open!
Keep the pictures coming.

 

[Wm McNett]

Thank you so much. I've been reading the repair manual for hours and I've filled in many of the blanks about these valves. There are a few differences though... the repair manual in the link shows spool wipers that are held in place by a retaining clip and two screws. There are no such items on my valves. Also... the manual show spacers between the valve sections at the point where the long shaft passes through the valves (at the point where the “Load Check” valve is secured by the shaft). There were no spacers between my valve sections but the seal kit that I purchased years ago does have the spacers included along with the 4 “O” rings that seal each valve to the next. I don't know if I should use the spacers or not but I can tell you this.... they are very very thin, only .003” (three thousandths) thick.

bTw... I soaked the cast valve bodies overnight in a degreaser I bought at Auto Barn and take a look at what the stuff did...

That's the best paint remover I've ever used. All it took was a light wipe with a wire brush... no real pressure... and the cast valve body shined almost like new.

“the repair manual in the link shows spool wipers that are held in place by a retaining clip and two screws. There are no such items on my valves.”
Pre October 1986 valves have a grove for the spool seal, after that they have a counter bore for the spool seal and the spool wiper.

 

[Jyuma]

“the repair manual in the link shows spool wipers that are held in place by a retaining clip and two screws. There are no such items on my valves.”
Pre October 1986 valves have a grove for the spool seal, after that they have a counter bore for the spool seal and the spool wiper.

Thanks... that explains it. My valves have the grove located inside the valve body.
Well... Murphy got me. I ordered the valve kits over 10 years ago and just never got around to rebuilding the valves. I must have had a leak even back then otherwise why would I have ordered the kits?
The 6 valves plus the end cap means 7 sets of “O” rings are required to connect the valves together and sure enough... there are 7 sets of “O“ rings in the kit. The only problem is that the end cap uses different size “O” rings than the valves and the kit I have has 7 identical sets of “O” rings. That means I can't even begin the final reassembly of the valve until I locate a set of “O” rings for the end cap.
Being that the “O” rings are just sandwiched between a groove on one side and a flat surface on the other, would it be okay to replace the “O” rings with any “O” ring that will fit the groove and is .070 thick? (the old rings are .070 thick).
One side of the mating valves has a .050 deep groove cut around the 4 holes that take an “O” ring and the other side of the mating valve is just a flat surface.
Here is a photo of the grooved side.

And here is a photo of the flat side.

With a groove that is .050” deep and an “O” ring that is .070” thick, that means when the valves are bolted together the “O” ring will compress .020”. The grooves are around .100” wide. If the .070 thickness of the ring is compressed to .050 then the .020” must go someplace and I'm assuming it will go into the space left between the .070” “O” ring and the .100” groove width. The point being I think the OD and thickness of the ring are the critical dimensions and the rest (ring spread under compression) will take care of itself.
That being said... do you folks think that if I can find “O” rings at the Borg box store that have the right OD and are more or less 1/16“ inch thick that they should work okay?

 

[SkidRoe]

Thanks... that explains it. My valves have the grove located inside the valve body.
Well... Murphy got me. I ordered the valve kits over 10 years ago and just never got around to rebuilding the valves. I must have had a leak even back then otherwise why would I have ordered the kits?
The 6 valves plus the end cap means 7 sets of “O” rings are required to connect the valves together and sure enough... there are 7 sets of “O“ rings in the kit. The only problem is that the end cap uses different size “O” rings than the valves and the kit I have has 7 identical sets of “O” rings. That means I can't even begin the final reassembly of the valve until I locate a set of “O” rings for the end cap.
Being that the “O” rings are just sandwiched between a groove on one side and a flat surface on the other, would it be okay to replace the “O” rings with any “O” ring that will fit the groove and is .070 thick? (the old rings are .070 thick).
One side of the mating valves has a .050 deep groove cut around the 4 holes that take an “O” ring and the other side of the mating valve is just a flat surface.
Here is a photo of the grooved side.

And here is a photo of the flat side.

With a groove that is .050” deep and an “O” ring that is .070” thick, that means when the valves are bolted together the “O” ring will compress .020”. The grooves are around .100” wide. If the .070 thickness of the ring is compressed to .050 then the .020” must go someplace and I'm assuming it will go into the space left between the .070” “O” ring and the .100” groove width. The point being I think the OD and thickness of the ring are the critical dimensions and the rest (ring spread under compression) will take care of itself.
That being said... do you folks think that if I can find “O” rings at the Borg box store that have the right OD and are more or less 1/16“ inch thick that they should work okay?

Hi Ed,
They are likely standard size O-rings, but you may have to go to a proper industrial supply store to get the exact right ones. What are the ID and OD of your grooves?
Here is a link to the Parker O-ring handbook. All O-rings use a standard sizing system, which contains a three number suffix (i.e. -XXX). Buna or Nitrile materials should work fine in your application.
http://www.parker.com/literature/ORD 5700 Parker_O-Ring_Handbook.pdf
When sizing your O-ring, select a size that has an OD very close (but slightly smaller) to the OD of your groove. That way your, O-ring will not flex very much when it comes under pressure.
Hope this helps,
SR

 

[Jyuma]

Hi Ed,
They are likely standard size O-rings, but you may have to go to a proper industrial supply store to get the exact right ones. What are the ID and OD of your grooves?
Here is a link to the Parker O-ring handbook. All O-rings use a standard sizing system, which contains a three number suffix (i.e. -XXX). Buna or Nitrile materials should work fine in your application.
http://www.parker.com/literature/ORD%205700%20Parker_O-Ring_Handbook.pdf
When sizing your O-ring, select a size that has an OD very close (but slightly smaller) to the OD of your groove. That way your, O-ring will not flex very much when it comes under pressure.
Hope this helps,
SR

SkidRoe... Thanks for the great information.
From the link you provided I determined that the O-ring I need is an AS568-020. Ordered 100 of them for 5 bucks... can't beat that with a hammer.

The order won't arrive until Aug 1st or 2nd so not much to do until then but wait.
Thanks again
Ed

 

[SkidRoe]

SkidRoe... Thanks for the great information.
From the link you provided I determined that the O-ring I need is an AS568-020. Ordered 100 of them for 5 bucks... can't beat that with a hammer.
The order won't arrive until Aug 1st or 2nd so not much to do until then but wait.
Thanks again
Ed

Cool, Ed. No worries, glad I could help.
Cheers,
SR

 

[Jyuma]

Cool, Ed. No worries, glad I could help.
Cheers,
SR

Got the O-ring I've been waiting for today and immediately went to work putting the valve back together.
Here's a photo of the new O-rings in their respective grooves in valve one...
Notice the green spacer in position on the shaft to the left in the photo. These green spacers were missing in the valves when I disassembled them.

Everything was going great until I got to the last valve... #6. Notice anything strange in this photo?

Want a closer look?...

Yup... a crack. Funny thing is that the valve wasn't leaking at #6... it was leaking at #5. Even when I used the outriggers to tilt the backhoe so #5 valve was up and #6 valve was down, the leak was still coming from #5.
I finished assembling the valves even though there is clearly a crack in #6. I'll skip the paint on the valve assembly for now and go directly to installing it on the machine. I'll have a better chance of seeing where the leak is coming from (if it in fact leaks) without the paint getting in the way.

 

[Tazza]

Got the O-ring I've been waiting for today and immediately went to work putting the valve back together.
Here's a photo of the new O-rings in their respective grooves in valve one...
Notice the green spacer in position on the shaft to the left in the photo. These green spacers were missing in the valves when I disassembled them.


Everything was going great until I got to the last valve... #6. Notice anything strange in this photo?

Want a closer look?...

Yup... a crack. Funny thing is that the valve wasn't leaking at #6... it was leaking at #5. Even when I used the outriggers to tilt the backhoe so #5 valve was up and #6 valve was down, the leak was still coming from #5.
I finished assembling the valves even though there is clearly a crack in #6. I'll skip the paint on the valve assembly for now and go directly to installing it on the machine. I'll have a better chance of seeing where the leak is coming from (if it in fact leaks) without the paint getting in the way.

You really can't win......
Can you see how far the crack extends? Cracks can be repaired, i'm currently in the process of repairing some Kubota heads with cracks. The hardest part is the machining, that's whats taking the time. I stitched the cracks with metal plugs, that was't too hard, but some where a pain to get the angles, yours should be pretty straight forward.

 

[Jyuma]

You really can't win......
Can you see how far the crack extends? Cracks can be repaired, i'm currently in the process of repairing some Kubota heads with cracks. The hardest part is the machining, that's whats taking the time. I stitched the cracks with metal plugs, that was't too hard, but some where a pain to get the angles, yours should be pretty straight forward.

I could weld the crack and then mill the surface flat or maybe try some crack repair like the kind used to repair cracks in windshields. I realize that the area is under high pressure, but the total area of the crack is so minute that very little total pressure would be exerted on the repair. I may even grind a “V“ groove along the crack and fill it with J-B Weld. Maybe that stuff is the miracle they advertise it as.
At this point I'm not certain what I will do. If it doesn't leak too badly I might just live with it and attach something under the control to catch the occasional drip. I won't know for certain until I put the valve back in the machine and apply pressure.
Now that I have all new O-rings in the valves, I'm fairly certain that I can eliminate the seals as a source of any leaks so if it does leak then it is likely coming from either this crack or others (possibly) that I didn't see.

 

[Tazza]

I could weld the crack and then mill the surface flat or maybe try some crack repair like the kind used to repair cracks in windshields. I realize that the area is under high pressure, but the total area of the crack is so minute that very little total pressure would be exerted on the repair. I may even grind a “V“ groove along the crack and fill it with J-B Weld. Maybe that stuff is the miracle they advertise it as.
At this point I'm not certain what I will do. If it doesn't leak too badly I might just live with it and attach something under the control to catch the occasional drip. I won't know for certain until I put the valve back in the machine and apply pressure.
Now that I have all new O-rings in the valves, I'm fairly certain that I can eliminate the seals as a source of any leaks so if it does leak then it is likely coming from either this crack or others (possibly) that I didn't see.

Not sure i'd rely on JB being srong enough to hold that much pressure back. On a shaft, there is no force trying to push it out, but in a crack there will be force on the housing trying trying to make it open up. I'd rather go the welding route after grinding a V into it.

 

[Jyuma]

Not sure i'd rely on JB being srong enough to hold that much pressure back. On a shaft, there is no force trying to push it out, but in a crack there will be force on the housing trying trying to make it open up. I'd rather go the welding route after grinding a V into it.

I contacted the guy Wm McNett mentioned in a post a few days back and I can't tell you how glad I am that I did. This guy is way more helpful then he needs to be and it may be looking like I may be able to replace individual valve sections.
I might need to replace #5 and #6 together because the old style spool O-rings are mounted inside the valve and the newer style spool O-rings are held in place by a retainer that uses the same mounting holes that my linkage assemblies use. In other words... I can't mount the O-Ring retainer and the control linkages at the same time... I could only connect one or the other.
If you're curious as to why, just look at the exploded view of my valve I posted back a ways and you'll see that there is a cast housing that supports the joystick for the BH boom controls and it is secured using the tapped holes on the top of the valve. These are the very same holes used to secure the O-Ring retaining clip on the newer style valves.
No biggie... worst case I'll replace both #5 and #6 valves and replace the old style joystick with the newer style joystick that mounts totally differently and does not require the O-Ring retaining clip mounting holes be used.

 

[Tazza]

I contacted the guy Wm McNett mentioned in a post a few days back and I can't tell you how glad I am that I did. This guy is way more helpful then he needs to be and it may be looking like I may be able to replace individual valve sections.
I might need to replace #5 and #6 together because the old style spool O-rings are mounted inside the valve and the newer style spool O-rings are held in place by a retainer that uses the same mounting holes that my linkage assemblies use. In other words... I can't mount the O-Ring retainer and the control linkages at the same time... I could only connect one or the other.
If you're curious as to why, just look at the exploded view of my valve I posted back a ways and you'll see that there is a cast housing that supports the joystick for the BH boom controls and it is secured using the tapped holes on the top of the valve. These are the very same holes used to secure the O-Ring retaining clip on the newer style valves.
No biggie... worst case I'll replace both #5 and #6 valves and replace the old style joystick with the newer style joystick that mounts totally differently and does not require the O-Ring retaining clip mounting holes be used.

Hopefully welding it will fix it, its cheaper than new valve sections..... I guess it will fix it or make it worse. As long as you have a way to repair it, nothing is lost from trying.

 

[skidsteer.ca]

Hopefully welding it will fix it, its cheaper than new valve sections..... I guess it will fix it or make it worse. As long as you have a way to repair it, nothing is lost from trying.

Grind the casting someplace where it does no matter as a test. If you get lots of grinding sparks then it is a good grade of cast and you may be able to have it welded.
JB would never work imo.
Ken

 

[Jyuma]

Grind the casting someplace where it does no matter as a test. If you get lots of grinding sparks then it is a good grade of cast and you may be able to have it welded.
JB would never work imo.
Ken

I think I located a replacement valve segment for #6. My valve looks exactly like a Parker/Munice V20T
P/N 08650008 Model 20T-10-04
Not cheap... but not too bad either... 100 bucks USD.
Now I wait again for the mail. tap... tap... tap...

 

[Jyuma]

I think I located a replacement valve segment for #6. My valve looks exactly like a Parker/Munice V20T
P/N 08650008 Model 20T-10-04
Not cheap... but not too bad either... 100 bucks USD.
Now I wait again for the mail. tap... tap... tap...

Nope!!! Close but no cigar, but the guy was nice enough to refund my money. I really didn't expect that.

 

[Jyuma]

Nope!!! Close but no cigar, but the guy was nice enough to refund my money. I really didn't expect that.

I'm back in the hunt for a replacement valve and this time it really looks like I found one but I'm unsure of the abbreviations I'm seeing in the description.
Here is the best picture I can find from the site in the UK that claims to have the valves in stock:

KA10 A1 SPADE END SR BLANKED
The KA10 is no problem... that's the type of valve. Parker already indicated that my valve was probably a KA10/18 and the Thomas Service manual says the valve is a Unit 10... So far so good.
The A1 isn't a problem either because I can see A1 stamped into all six of my valves.
Even the Spade End is OK.
That brings me to my problem... what the H... is SR Blanked? I can make a few guesses... like System Relief is blanked... meaning there is no pressure relief valve in this segment but I really don't know.
This valve (if I order it) will be shipped from the UK and although the price of the valve is reasonable... about $85 USD... I'm sure the shipping is going to high, so I'd like to be 100% certain that this is the right valve but I can't be certain until I know what SR Blanked means.
I also saw many other entries used in the descriptions that I don't understand, like...
KONTAK DC/SC JIC PORTS FORKED
KA10 A2 D.A.DETENT S.END 02156
KA10 D2 MOT DETENT SPADE END
KA10 B2 S.A. DETENT FORKED END
KA10 C1 D.A. FLOAT S END C/W SRV
Does anybody know what all this stuff means? Ports forked and D.A. Detent or D.A. Float?

 

[Wm McNett]

I'm back in the hunt for a replacement valve and this time it really looks like I found one but I'm unsure of the abbreviations I'm seeing in the description.
Here is the best picture I can find from the site in the UK that claims to have the valves in stock:

KA10 A1 SPADE END SR BLANKED
The KA10 is no problem... that's the type of valve. Parker already indicated that my valve was probably a KA10/18 and the Thomas Service manual says the valve is a Unit 10... So far so good.
The A1 isn't a problem either because I can see A1 stamped into all six of my valves.
Even the Spade End is OK.
That brings me to my problem... what the H... is SR Blanked? I can make a few guesses... like System Relief is blanked... meaning there is no pressure relief valve in this segment but I really don't know.
This valve (if I order it) will be shipped from the UK and although the price of the valve is reasonable... about $85 USD... I'm sure the shipping is going to high, so I'd like to be 100% certain that this is the right valve but I can't be certain until I know what SR Blanked means.
I also saw many other entries used in the descriptions that I don't understand, like...
KONTAK DC/SC JIC PORTS FORKED
KA10 A2 D.A.DETENT S.END 02156
KA10 D2 MOT DETENT SPADE END
KA10 B2 S.A. DETENT FORKED END
KA10 C1 D.A. FLOAT S END C/W SRV
Does anybody know what all this stuff means? Ports forked and D.A. Detent or D.A. Float?

I'm guessing you found Hy-Power OR White House
http://www.hy-power.com/kwresults.asp?st=ka10&s3=Find&ct=AND&nr=10&qt=1&offset=0
http://www.whitehouseproductsltd.com/search-results.aspx?kw=KA10
Forked / Spade is the spool end

Detent is going to stay where you put it.
Float has a 4th detent position that will allow whatever to move freely. Like whats on the boom for most front end loaders.
JIC is flared 37º
I'm going to guess the SR Blanked does not the hole for the Service Relief valve

Hope I helped

 

[Jyuma]

I'm guessing you found Hy-Power OR White House
http://www.hy-power.com/kwresults.asp?st=ka10&s3=Find&ct=AND&nr=10&qt=1&offset=0
http://www.whitehouseproductsltd.com/search-results.aspx?kw=KA10
Forked / Spade is the spool end

Detent is going to stay where you put it.
Float has a 4th detent position that will allow whatever to move freely. Like whats on the boom for most front end loaders.
JIC is flared 37º
I'm going to guess the SR Blanked does not the hole for the Service Relief valve

Hope I helped

Yup. Very helpful.
I'm working from the hy-power site because they have pictures.

So I guess the valve I showed is the right valve... maybe? The one I need to replace doesn't have any relief valves in it... in fact, it doesn't even have a position for a relieve valve in the valve casting.
It looks like the spool end is right... and the spring will return the spool to center... and there is no detent. The specification sheets that I got from Parker for the KA10/18 valve contains dimensions that agree with my valves, so I'm getting real close to calling this the right valve.
Only one more thing to do before ordering the valve... ask the guy at Parker to verify that it is the right valve. Maybe even order it from him.