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SPArKy_Dave

Weber Carb 34ADM Master Thread

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(additional pics/info added - 03-03-23)

 

The Italian made Weber 34adm Carburetor, was factory fitted to XE/XF Falcon 6cyl, Ford F100-350's and Ford Bronco 6cyl.

It existed as factory fitment, from mid 1982, up till March 1993 - when the XF Falcon commercial range ended, and the XG Falcon was launched.

 

The stock 34adm carby, has a flow rate of 230cfm. (see flow test pic, further down)

 

For an easy upgrade, a 38/38 Weber carburetor has a 390cfm flow rate,

and bolts directly to the stock intake manifold.

 

The purpose of this thread, is to have Technical and Parts info for the Weber 34adm Carburetor, all in one location.

I will edit and add to this first post, as I find further info.

 

If anyone has any additional info on these carby's, they're most welcome to add it into the thread.

 

34ADM-schematic.jpg

 

WEBER 34ADM 1 Parts Diagram 1a.png

 

WEBER 34ADM 1 Parts Diagram 2.png

 

WEBER 34ADM 1 Parts Diagram 3.png

 

 

 

Exploded_view_of_WEBER_34_ADM_0_USD.pdf

 

Weber 34adm parts diagram 1a.jpg

 

List of parts:

No Part No Price Pcs Description
1 31716.461 $ 0 1 Carb Top Cover
2 37022.004 $ 10.3 1 Filter element
3 64700.005 $ 0 6 Top Cover Fixing Screw
4 64010.034 $ 0 1 Choke throttle valve
5 64525.003 $ 0 2 Choke plate fixing screw
6 10015.274 $ 7.8 1 Choke shaft
7 10140.501 $ 1 1 Locking Ring
8 41565.008 $ 0.8 1 O ring
9 55510.034 $ 0.4 2 Lock Washer
10 64700.001 $ 5 2 Fixing Screw
11 52135.018 $ 3 1 Dust seal plate
12 61070.002 $ 3 1 Dust seal plug
13 57804.446 $ 0 1 Auto Choke Assy. Including
14 64560.004 $ 0 3 — Diaphragm cover fixing screw
15 64595.005 $ 5.8 1 — Diaphragm adjusting screw
16 32384.060 $ 0 1 — Diaphragm cover
17 47600.229 $ 0 1 — Diaphragm loading spring
18 47407.226 $ 0 1 — Choke diaphragm
19 47605.030 $ 0 1 - Return Spring
20 41640.052 $ 3 1 Auto Choke Body Gasket
21 57804.483 $ 0 1 Autochoke Thermostat
22 52135.029 $ 2.4 1 Choke Lock Ring
23 64615.004 $ 0 3 Screw
24 52570.006 $ 6.5 1 Idling jet holder
25 41565.002 $ 0.4 1 Idle jet holder O Ring seal
26 74403.060 $ 3 1 Secondary idle jet
27 64700.010 $ 0 2 Fixing Screw
28 55510.038 $ 0 2 Lock Washer
29 31800.027 $ 0 1 Capsula minimo accelerato
30 - $ 0 1 Carburetor Body
31 47600.007 $ 2.3 1 Idle Screw Spring
32 64625.012 $ 6.5 1 Throttle Adjustment Screw
33 64595.013 $ 0 1 Secondary throttle adjusting screw
34 67016.092 $ 0 1 Carburettor shaft base. including:
35 10000.264 $ 0 1 Primary Throttle Shaft
36 41575.010 $ 3.2 1 Bushing
37 10015.273 $ 0 1 Secondary Throttle Shaft
38 64005.113 $ 0 2 — Throttle valve
39 64520.027 $ 0.6 4 Throttle plate screw
40 45048.124 $ 0 1 Throttle control lever
41 64595.035 $ 0 1 Throttles adjusting screw
42 34715.014 $ 1 1 Throttle Spindle Nut
43 55520.002 $ 1 1 Shaft Lock Tab
44 12775.092 $ 0 1 Boccola guida leva allentata
45 45069.092 $ 0 1 Lever
46 47610.175 $ 0 1 Molla leva allentata
47 47610.091 $ 0 1 Choke lever return spring
48 55555.019 $ 0.9 1 Shaft Spacer
49 41575.010 $ 3.2 2 Bushing
50 64700.016 $ 0 2 Fixing Screw
51 55510.018 $ 0 2 Lock Washer
52 61075.013 $ 4 1 Idle mixture tamper proof plug
53 64750.080 $ 0 1 Idle Mixture Screw
54 41565.010 $ 0 1 Idle Mixture Screw O Ring
55 39152.015 $ 0 1 Base Spacer Heat Gasket
56 43914.060 $ 0 1 Idle Cut Off Solenoid
57 55530.020 $ 0 1 — Rosetta ondulata
58 74409.060 $ 3 1 — Idle jet
59 41535.024 $ 0 1 Guarnizione Intercettatore minimo
60 34710.003 $ 1 1 Throttle Shaft Nut
61 55520.004 $ 1 1 Throttle Shaft Lock Washer
62 14850.140 $ 0 1 Pump Cam
63 12750.103 $ 0 1 Boccola distanziale leva allentata
64 55530.014 $ 0 1 Rosetta ondulata leva allentata minimo accel.
65 45067.048 $ 0 1 Leva allentata comando mimmo accelerato
66 10140.304 $ 0 1 Anello elastico ritegno leva allentata
67 55510.081 $ 1.2 1 Washer For Shaft
68 55525.001 $ 0 1 Spring Washer
69 34705.001 $ 0.8 1 Secondary shaft fixing nut
70 47600.092 $ 0 1 Pump Spring
71 47407.146 $ 0 1 Pump diaphragm
72 32486.084 $ 0 1 Accelerator Pump Cover
73 64565.001 $ 0 2 Screw
74 64700.019 $ 0 2 Pump Cover Screw
75 34715.003 $ 0 1 Nut 
76 32240.501 $ 0 1 Interruttore unipolare
77 14975.081 $ 0 1 Cavo unipolare
78 58510.008 $ 0 1 Staffa interruttore
79 47407.182 $ 0 1 Membrana valvola piena potenza
80 47600.005 $ 3.5 1 Starter Valve Spring 
81 32384.046 $ 0 1 Coperchio valvola piena potenza
82 64565.001 $ 0 3 Screw
83 64565.001 $ 0 4 Screw
84 52000.015 $ 1.1 1 Float pivot
85 32484.044 $ 0 1 Coperchio pompa pneumatica
86 47600.279 $ 0 1 Spring For Diaphragm
87 47407.163 $ 0 1 Membrana pompa pneumatica
88 73801.210 $ 3.7 1 Main jet
88 73801.140 $ 3 1 Main jet
89 61440.220 $ 9 1 Primary Emulsion Tube
89 61440.491 $ 0 1 Secondary Emulsion Tube
90 77201.160 $ 3 1 Secondary air correction jet
90 77201.170 $ 3 1 Primary Air Corrector Jet
91 76407.060 $ 13 1 Pump jet
92 41565.001 $ 0 1 Pump Jet ´O´ Ring
93 41565.008 $ 0.8 1 O ring
94 61075.002 $ 0 1 Tappo coperchio sgolfatore
95 70508.450 $ 0 1 Auxiliary Venturi Secondary
95 70508.450 $ 0 1 Auxiliary Venturi Primary
96 41705.072 $ 0 1 Top Cover Gasket
97 41015.004 $ 33.2 1 Float
98 79510.175 $ 0 1 Needle & Seat
99 83102.070 $ 1 1 Gasket for Needle Valve
100 43921.100 $ 0 1 Intercettatore ricircolo completo di:
101 55530.016 $ 0 1 — Wavy Washer
102 58000.019 $ 0 1 — Cup Washer
103 41565.001 $ 0 1 — Idle jet holder O Ring seal
104 74409.100 $ 3 1 — Idle jet
105 61002.019 $ 0 1 Fuel Filter Cover

 

 

34adm.JPG

 

1. Throttle nudger: On the XE/XF Falcons this is used to hold the throttle open slightly during an overrun condition by applying vacuum at the hose fitting. The screw in the top sets how much the throttle is held open.

2. Accelerator pump accumulator: Receives the fuel charge from the accelerator pump and controls the discharge rate of the fuel into the air stream.

3. Fuel inlet fitting.

4. Fuel filter plug. There is a small plastic filter under this plug.

5. Fuel return. On some models this is used to return fuel to the fuel tank when item 6 (below) is fitted.

6. Fuel return solenoid fitting. On some models there is a solenoid screwed into this fitting that energises when the throttle is closed, allowing fuel to return to the tank when at idle.

7. Idle solenoid. Allows fuel to flow in the idle circuit when this solenoid is energised. +12 Volts must be applied to this solenoid when the ignition is switched on.

8. Power bypass circuit actuator diaphragm. Allows fuel to flow in the power bypass circuit when low manifold vacuum is sensed.

9. Accelerator pump lever.

10. Electric automatic choke mechanism. Under the green plastic cover there is a heater element and a bi-metallic spring. +12 Volts is applied to the threaded stud in the centre when the ignition is on. The heater element heats up and in time, causes the bi-metallic spring to rotate the choke shaft, causing the choke to open. Loosening the three screws allows the cover to rotate, to adjust the choke to the correct fully open position after warm-up.

11. Fast idle screw. Adjusts the fast idle speed. Operates whenever the choke is partially closed. There are several steps of fast idle due to the operation of a stepped cam inside the choke mechanism. Adjustment should be made for fast idle on the first step after a cold start. Do not use this screw to adjust the normal idle speed.

12. Choke pull-off diaphragm. Cracks the choke open slightly as soon as the engine starts. Under the small brass plug at the centre there is a grub screw that adjusts how much the choke is cracked open.

13. Accelerator pump. Pumps fuel into the air stream, via the accelerator pump accumulator, during hard acceleration.

14. Idle speed screw. Adjusts the idle speed. To be adjusted only after the engine has reached operating temperature, and the choke is fully open.

15. Vacuum advance connection. Connects to the distributor vacuum advance diaphragm.

16. Idle mixture screw. Adjusts the idle fuel/air mixture.

 

 

jet sizes.jpg

 

Stock jetting for 3.3l and 4.1l Crossflow Weber 34adm carburettor-

 

First stage Idle: 60

Second stage Idle: 70

Primary Fuel: 135

Secondary Fuel: 210

Primary Air: 160

Secondary Air: 160

 

The following jetting, apparently gives excellent throttle response, very smooth idling and excellent pickup on secondaries -
(stock 3.3l Crossflow Motor)

 

Primary Idle: 65
Secondary Idle: 75
Primary Fuel: 140
Secondary Fuel: 220
Primary Air: 160
Secondary Air: 180

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DIS-ASSEMBLY AND REBUILD INFORMATION -

 

image.png.3ae63d3eb1969d6982e371123fb6713b.png

 

image.png.2ab184bd3115368e173ab1a277ee6949.png

 

image.png.e979b857138ccfea7f4e96345ac693b2.png

 

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image.png.83ea74061e55cd7aa4ea9e969179bfcc.png

 

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https://oldschool.co.nz/index.php?/topic/75342-weber-34-adm-carb-conversion-info/

 

Weber 34ADM carburettors, have a 2 stage low speed jet solenoid.

This was an emissions control system, which allowed the engine to run with one jet size when cold (70)

and when the engine warmed up it switched to a smaller jet to reduce emissions (55).

 

As the idle jet vacuum solenoid ages, the little diaphragm inside fails allowing - fuel to flow from the primary low speed circuit through the failed solenoid

and into the line that supplies vacuum to the system.

This causes the engine to run super rich.

 

Products which can solve the problem can be found at the below links,

comprising of a larger jet holder, which deletes the solenoid and the appropriate jets to go with it.

 

You may need to mess around with the jets to find the right one for your engine

 

https://www.weberperformance.com.au/product_info.php?cPath=6_268&products_id=631

https://www.weberperformance.com.au/product_info.php?cPath=6_268&products_id=1345

 

Here is a picture of the system on the standard carb

and of another of the carb, with the idle jet solenoid system deleted.

 

You will note all the vacuum ports except the vacuum advance are capped off, deleting the emissions control systems

(EGR etc).

 

image.png.87482af0431ef2777a6d23eb063124a3.png

 

image.png.c619bdb351f07521f4de768e8a58a917.png

 

This pic shows the throttle nudger, which is supposed to hold the throttle slightly open momentarily if the throttle is snapped shut suddenly to smooth things out.

On some models it may also have been supplied vacuum as an idle up system for air con etc.

 

The diaphragm can fail and cause a vacuum leak and most of the carb rebuild kits don't include this particular diaphragm.

 

image.png.7162f43d160464f10998b7d4aeb46bdd.png

 

The vacuum port for the power valve is in an odd place on these carbs and some off the shelf adaptor plates will blank it off causing the engine to run on the power valve all the time and run very rich. 

The port is actually under the base plate and is not open to either of the carb barrels.

 

If this port is omitted, vacuum will not be supplied to the power valve or the accelerator pump boost diaphragm and the carb simply wont work properly.

 

If you look at the underside of the carb you will find the port (it might even be blocked with crud).

The port is located between the primary and secondary bores and continues up through base and into a tube in the carb body.

 

The tube also acts as a locating dowel and can sometimes become damaged and obstructed if the carb hasn't been assembled correctly at some stage in the past.

 

image.png.2777b68bc61815deb26d53e0aeff54a0.png

 

 

 

Further useful info can be found here -

http://www.mbs.id.au/tuning/Carburettors/Weber/34ADM.htm

 

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There are five springs in total fitted in this carb. By process of elimination you can work out several of them but some are interchangable and if fitted incorrectly will cause mixture problems. So keep the springs with their correct counterpart.

 

image.png

 

Shown are the vacuum passages to the power valve diaphragm and the boost accelerator pump. When vacuum drops to a pre-determined level the power valve diaphragm is pushed into the power jet which opens the ball to allow more fuel into the main circuit. Also the loss of vacuum applies an extra amount of fuel to the accelerator pump circuit over and above what the accelerator pump diaphragm will deliver. This will usually occur when the second barrel is opened suddenly. The different spring length & tension will operate these devices at differing vacuum settings.

 

image.png

 

The vacuum to the power valve & accelerator pump boost diaphragms is supplied through this tube. The vacuum port continues down through to the base of the carb between the primary and secondary bores. The tube also acts as a location dowel. It is long enough to pass through the thick gasket and into the base. Now what can happen is that if you don't line up the dowel perfectly to the base and you attempt to tighten the base screws then the tube can be pushed further into its bore in the body of the carb. The end result is a blocked vacuum passage. This will result in a rich cruise mixer and a hesitation when the second barrel opens suddenly. To check that the passage is unobstructed, place you mouth on the tube and suck or attach a tight hose and suck on it. It should feel easy to suck through. If not then this is what needs to be done.

 

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Remove the tube and the easiest way to do this is to stick a drill into the tube, then use a small pair of vice grips to grip it and twist it out. Cut a slot into the tube and then refit it back into the hole. Make sure the slot lines up with the vacuum passage and the tube protrudes through the thick gasket so it can line up with the base. The slot does not have to be as long as in the photo. If the tube is fitted at the correct depth, this mod would be unnecessary.

 

 

REBUILD KIT LINKS -

 

 

https://www.ebay.ca/itm/FORD-FALCON-WEBER-34-ADM-SERVICE-KIT/264174927546?epid=2102017418&hash=item3d820d7eba:g:kYYAAOSwFV9X1ukr

 

https://www.ebay.com.au/itm/WEBER-34-ADM-CARBURETTOR-SERVICE-KIT-FORD-FALCON-3-3-4-1/201732658915?hash=item2ef83416e3:g:RbgAAOSwa~BYPWPJ

 

https://www.meat-doria.com/en/product_meat/W552.1

https://www.meat-doria.com/en/product_meat/W552

 

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Flow testing a stock 34adm carburettor

 

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wouldn't mind seeing how the power valve itself comes out, one of mine here is stuck on.. making the engine flood. pretty sure it's pressed in and can't be removed(not without butchery)

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Excellent information.

However I found those kits you list to be incomplete and poor quality. The pump plunger in those kits have a plastic end which can wear quickly or melt when fuel gets on them. Plus the intermediate gasket is just a paper gasket and does not work if your carby has already been overhauled in the past. You need the complete block gasket. There is no auxiliary diaphragm in those kits which is a must. Most of those kits do not have a choke pulloff and the kit that does is missing all the top plastic parts and spring. Those kits are also missing the large acd diaphragm. 

A better company to deal with is Partsdencom, they have the best kits around and as they are in Australia it only takes 1-3 days to get the parts you need.

 

Minor kit:

https://www.ebay.com.au/itm/223851328759

Major kit:

https://www.ebay.com.au/itm/223132643529

Major kit with new filter screen:

https://www.ebay.com.au/itm/202875656729

New replacement electric choke unit:

https://www.ebay.com.au/itm/202106652566

Replacement nitrophyl float for the brass float, a must if you run your car on LPG:

https://www.ebay.com.au/itm/202106654779

Thick base gasket:

https://www.ebay.com.au/itm/192730586312

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On 7/11/2021 at 10:53 AM, The carby guy said:

Excellent information.

However I found those kits you list to be incomplete and poor quality. 

A better company to deal with is Partsdencom, they have the best kits around and as they are in Australia it only takes 1-3 days to get the parts you need.

 

Major kit with new filter screen:

https://www.ebay.com.au/itm/202875656729

 

Yes. Some of the cheaper kits miss most of what needs to be replaced. Also +1 for partsden.

I used to get the "Fuel Miser" kits of which you would have a lot of extra parts that you did not need.

Recently I have fitted the full kit from partsden and there is a marked improvement especially with cold start and idle.

 

Overall I find the 34 ADM carburettor very satisfactory requiring minimal adjustments. Fitting a major kit every 5 years gives these engines a marked rejuvenation.

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Sorry if this is the wrong thread, but I can't seem to navigate the search function to find my answer, and Google is proving difficult.

This thread states that the 34adm is in the XE/XF. I have a 1979 XD 4.1 and would like to know what the factory fitted carby is.

 

Cheers

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2 minutes ago, BDuck said:

Sorry if this is the wrong thread, but I can't seem to navigate the search function to find my answer, and Google is proving difficult.

This thread states that the 34adm is in the XE/XF. I have a 1979 XD 4.1 and would like to know what the factory fitted carby is.

 

Cheers

stomberg single barrel,. if it looks like this https://www.ebay.com.au/itm/143667442469

VAM7XBF.jpg

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18 minutes ago, BDuck said:

Thanks for the quick reply! I take it the upgrade path is not a straight swap like what's recommended in here?

most people who fit a bigger carby to the iron head (1979 XD) would get the XC/XD redline manifold and fit a 350 holley (could adapt it to a weber if preferred) 

if it was an XD 1981 with Alloy head, the XE/XF manifold fits, but it's a bit of a muck around to get working on an XD still, (throttle cable ball is different size, no choke output on the alternator, something else i can't remember)

if it was mine, i'd keep it stock and find a carby kit if required. they drink a bit of petrol but i'd suspect it's not a daily driver doing heaps of kms, the stromberg is pretty reliable. 

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13 minutes ago, deankdx said:

most people who fit a bigger carby to the iron head (1979 XD) would get the XC/XD redline manifold and fit a 350 holley (could adapt it to a weber if preferred) 

if it was an XD 1981 with Alloy head, the XE/XF manifold fits, but it's a bit of a muck around to get working on an XD still, (throttle cable ball is different size, no choke output on the alternator, something else i can't remember)

if it was mine, i'd keep it stock and find a carby kit if required. they drink a bit of petrol but i'd suspect it's not a daily driver doing heaps of kms, the stromberg is pretty reliable. 


It's more out of interest of what I can do/if I can do it. Car is essentially single owner from factory considering it was my grandparents' car (still have the original registration cert and warranty/maintenance booklet) and yeah, car has just over 200,000kms so the stromberg definitely seems reliable.

 

Thanks again

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Hey guys,

 

Maybe someone can weigh in here. Trying to get a manual choke setup for a 34ADM, I found nothing in Aus but a shop in the UK has this which will fit a Weber 34ADF. My google fu says they're very similar and it looks to me like it would fit. Anyone happen to know if they might be the same? I'd imagine there's a good chance it would fit.

 

https://classiccarbs.co.uk/product/weber-3236-dgav-38-dgas-carburettor-manual-choke-conversion-kit

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They've responded to my email, they don't have one to check but I've compared the measurements they've given for the kit below and it looks like it will bolt up at least.

 

Diameter of the choke assembly thing is the same and the holes for the plate are the same. The inside of it looks similar as well with the fork part there.

 

https://classiccarbs.co.uk/product/weber-dgav-dgev-dgv-dgas-dges-dgms-dfav-dft-manual-choke-conversion-kit

 

It really seems to me like it should fit but nothing is ever that easy.

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On 5/5/2023 at 12:53 PM, deankxf said:

did you try this mob in Melbourne, they know what a falcon 34ADM is

https://www.weberperformance.com.au/

 

On 5/5/2023 at 3:43 PM, Nath said:

Yeah tried them, no clue 

 

They've probably forgotten what a 34ADM even is...

I've encountered this before, with other 'old school' automotive things.

Similar to how most wheel alignment places, have forgotten how to align x-series.

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9 hours ago, SPArKy_Dave said:

They've probably forgotten what a 34ADM even is...

I've encountered this before, with other 'old school' automotive things.

Similar to how most wheel alignment places, have forgotten how to align x-series.

the people that know anything were likely 30-40yrs old when i got mine, that was 30yrs ago so they are likely retired or turned into managers/desk workers.

biggest reason i went to Pedders instead of "other aligners" is they check to see if the suspension is worn before doing one. (got an alignment from Bob Jane about 20yrs ago and it chewed tyres like it was going out of style, took it to pedders, LOOK HOW WORN THE IDLER ARM and TIE Rod is, no hope of aligning that. )

Carby expert i dealt with last was still working at age 67 but passed away probably age 68 ish(was only working part time 3 days a week)

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Update on this: The place in the UK emailed me back, DGV manual choke setup won't work as the locking ring is a different shape so the holes won't line up, their locking ring what the choke cable connects to so it's necessary. The element connection is also different, Weber has a tongue while DGV has a pin that attaches to the mechanism.

 

So as far as I can tell there's no manual choke setup for the 34ADM available.

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On 5/7/2023 at 10:54 AM, deankxf said:

LOOK HOW WORN THE IDLER ARM and TIE Rod is, no hope of aligning that. )


Carby expert i dealt with last was still working at age 67 but passed away probably age 68 ish(was only working part time 3 days a week)

 

The last x-series alignment I had done, was after hrs, by an old school mechanic I'd done some electrical work for.

First thing he did, was check that stuff, and found I needed new upper ball joints.

 

A few yrs ago, I bought an injector reco/test flow bench machine from a carby guru in Seaford.

He looked about that age - semi-retired, as he said he'd recently become ill with the big C.

Exposure to fuel or cleaning chemicals maybe?

My retired mechanic uncle, died a very similar way a few yrs ago - often called mechanics disease apparently.

 

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