bellcrank mod

1941 - 1945, MB, GPW modifications, sugestions, and ideas, official MWO's and unofficial WWII field mods NO EBAY or COMMERCIAL SALES.
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B Johnny Smith
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bellcrank mod

Post by B Johnny Smith » Sat Feb 08, 2020 3:33 pm

is anybody doing a brass bushing instead of the bearings at the bellcrank shaft?


amphibian
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Re: bellcrank mod

Post by amphibian » Mon Feb 10, 2020 5:07 pm

Hi ,I’ve been running with a bronze bush in the front bell crank for more than 10 years with no problems.

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Re: bellcrank mod

Post by Joe Gopan » Tue Feb 11, 2020 8:09 am

Brass Bellcrank Bushings installed in MB/GPW did exist and were a common find during and after WWII. I have encounted many over the years. I do not have the part number. The Needle Bearings were WO-A-857. Am sure many of you have encountered one
The Brass Bearing was one piece and had a square hole in the side at the halfway point for grease from the fitting.

I seem to remember that the brass bellcrank bearing was mentioned in one of the WWII editions of "Army Motors".
I may have one of these NOS Brass Bellcrank Bearings in with my steering parts.Will take a fast look tonite.
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bazza46
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Re: bellcrank mod

Post by bazza46 » Tue Feb 11, 2020 12:21 pm

The needle roller bearing in the bellcrank seems to have been a bit of 'over think' on the part of the designers. Such bearings are really good in high speed , fully rotational assemblies, such as small gears, two stroke crankshafts and big and little ends of conrods on small,, high revving two stroke engines. They work best where there is full rotation, as the rollers roll continuously, bathed in a mist of oil.

But on the jeep bellcrank, they stay mostly in the same position all their lives, with little directional turning, and when they do turn, it's very slow. As a result, from the pounding of the steering mechanism in from road use, the individual rollers pound, or brinell, a little groove on the spot where they are continually resting, and in relatively short time, give the shaft a fluted appearing surface. From that moment on, they don't even roll a bit on turning, but slip around in their individual grooves, till the shaft is rattly and loose. Tightening up the nut on top does not help for long, as the grooves are there permanently.
On the other hand, a proper fitting bronze bushing has full contact around the whole thrust side of the shaft, and when pounded by road shock, does not bash little flutes into the shaft. It takes the pounding on a full, smooth surface which has more surface area than the point contact of the rollers.
It does wear, but slowly and evenly, giving smooth movement to the bellcrank.
I've found that a well fitted bushing lasts longer than the rollers. Also, some (many) of the pivot shafts are not that hard, and the hardened rollers eat them up fast. But the bush rides nicely on a hardened or not so hard shaft.

I've got bushes on all my jeep bellcrank shafts.
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Rod Rushton
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Re: bellcrank mod

Post by Rod Rushton » Sun Feb 16, 2020 3:01 am

I am interested in changing the roller bush for a bronze or oilite one. I guess I would need to have one made, Can someone please post a photo or drawing of one?
Cheers
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Re: bellcrank mod

Post by GPW1263 » Sun Feb 16, 2020 7:58 am

bazza46 wrote:
Tue Feb 11, 2020 12:21 pm
The needle roller bearing in the bellcrank seems to have been a bit of 'over think' on the part of the designers. Such bearings are really good in high speed , fully rotational assemblies, such as small gears, two stroke crankshafts and big and little ends of conrods on small,, high revving two stroke engines. They work best where there is full rotation, as the rollers roll continuously, bathed in a mist of oil.

But on the jeep bellcrank, they stay mostly in the same position all their lives, with little directional turning, and when they do turn, it's very slow. As a result, from the pounding of the steering mechanism in from road use, the individual rollers pound, or brinell, a little groove on the spot where they are continually resting, and in relatively short time, give the shaft a fluted appearing surface. From that moment on, they don't even roll a bit on turning, but slip around in their individual grooves, till the shaft is rattly and loose. Tightening up the nut on top does not help for long, as the grooves are there permanently.
Very well said..and when you think about it, bearings supporting the steering king pins exist in a very similar circumstance. Such matters require additional care and maintenance. Thus, after acquiring an old jeep, these are good places to start looking for trouble.

Cheers,
TJ

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Re: bellcrank mod

Post by bazza46 » Sun Feb 16, 2020 12:01 pm

Hi TJ.
What you said about the kingpin bearings is quite right. In fact, manufacturers like Land Rover found them so unsatisfactory (because all the load rests on the bottom bearing only, for one thing), that on the early series they replaced the top one with a brass cone pressed tightly with a coil spring.

Even that wasn't so good, so aftermarket manufacturers like Quinton Hazell made a kit which had a parallel sided swivel pin riding in a cup lined with fibre. It worked well with the total area of the pin resting on the fibre taking the bashing stress.
s-l1600 2.jpg
And of course, the new four wheel drives have external ball joints, which really are a plain smooth ball resting in matching bushing.
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Re: bellcrank mod

Post by Joe Gopan » Sun Feb 16, 2020 2:42 pm

Hopefully a G503 member will have one of the brass bellcrank bushings I described.
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ozm29c
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Re: bellcrank mod

Post by ozm29c » Mon Feb 17, 2020 7:15 pm

Here is a photo of an Amphibious Jeep bell crank I recently fitted a brass bushing to.
Attachments
26Sep2019.jpgR.jpg
GPW 135997
M29C 7333
M29C 4338

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Re: bellcrank mod

Post by Joe Gopan » Wed Mar 04, 2020 7:27 am

Here are the components of the G-503 Bell Crank and the Bronze Bushing I discussed. I had to do some digging as I knew I saved an example of the bronze bushing, that was installed as a substitute for the two A-857 Torrington Needle Bearings. I do not Have the Part No. for the bronze bushing, but some of the suppliers may have a source old enough to remember it. There are two style TAPERED PINS, WO-856 (short), and 645421 (Long Tapered with threads) that are illustrated for the shaft. Will discuss later
Bell crank Kit 1.jpg
Bell crank Kit 2.jpg
Bell crank Kit 3.jpg
Bell crank Kit 4.jpg
Bell crank Kit 4jpg.jpg
Bell crank Kit 5.jpg
Bell crank Kit 7.jpg
Sorry for the small photos, haven't a clue what I did.
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HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
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Re: bellcrank mod

Post by Joe Gopan » Sun Apr 19, 2020 7:22 am

NOS Bellcrank Bushing from 40's-60's Jeep stock. These were availible from post war suppliers in the good old days. I have removed the bushing type from bellcranks that had no civilian use.
The bushings may have been discussed in WWII Army Motors Publication.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
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bryanbdp
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Re: bellcrank mod

Post by bryanbdp » Sun Jul 05, 2020 8:27 pm

I made a post in the tech section, but here is a print I made
bellcrank bushing.png
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Marty, SoCal
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Re: bellcrank mod

Post by Marty, SoCal » Tue Jul 07, 2020 5:08 pm

Technical Bulletin TB 9-803-FE6, "Reinforcement of Drag Link Bell Crank" Dated 23Jan45 is about reinforcing the bell crank with a 1-1/2" x 1-1/2" x 2-3/8" triangular wedge of 1/4" scrap steel arc welded into the vee of the bell crank. BUT it also includes info on changing the roller bearings to a "Hard Bronze Shackle Bushing" that may be modified and used to replace excessively worn needle bearings. It does not give a part number for the bushing. It says to press the bushing into the arm, drill a hole in the bushing for lubricant and ream to fit the bell crank pin with 0.002" clearance.

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Chuck Lutz
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Re: bellcrank mod

Post by Chuck Lutz » Tue Jul 28, 2020 11:27 am

GPW-3131 Bellcrank is listed up to the March 1943 TM 10-1348.
At some point, Ford went to the GPW-3131-B bellcrank which has some additional steel forming a "web" to strengthen it.
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