Prop shaft doesn't fit through the tunnel!!??

Technical advice Q&A

Topic author
Atomlinson275
Posts: 10
Joined: Mon Oct 17, 2022 2:11 pm
Great Britain

#1 Prop shaft doesn't fit through the tunnel!!??

Post by Atomlinson275 » Mon Apr 15, 2024 4:11 pm

I bought a replacement prop shaft from the usual suspects.

Looked really good although the black paint was quite poor. Especially in areas where the primer was missing?
I only know this as I stripped the black paint off very easily and found about half the surface area actually had any primer on it. Quality control - 'Nul points'

It gets even better.
I had fitted the engine and gearbox, so now it was time to fit my new shiny, freshly painted prop shaft. You would have thought this would be an easy quick job. Oh how wrong I was.
The prop shaft flange would not get past the constriction caused by the handbrake recess.
I thought I was going mad as it was so close to going through. I tried every which way but to no avail.
The flange would just not get passed.
I then measured the diameter of the flange and compared it with my knackered old shaft and found that it was 3 mm over on diameter. Quality control - 'Nul Points'

Image

Image

Just to do I final sanity check. I passed my old shaft along the tunnel and it passed without scratching the sides.

So here we go again another instance of aftermarket parts just not quite getting over the line with regard to fit and finish. I really do despair.
I am sure I could have rammed it up the tunnel and forced it through, scratching and damaging the sides of the tunnel and nobody will notice will they!!??

In the end I removed my flanges from the knackered original shaft and fitted them to my new prop shaft.
The next question is whether I now need to get it balanced?

So much for a 5 minute job!
Andy

1966 4.2 FHC
1989 Porsche 944
1995 LR Defender
1969 Daimler V8
1976 Triumph Bonnaville
1971 Kawasaki Z1

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

Series1 Stu
Posts: 1651
Joined: Thu Feb 02, 2017 12:26 pm
Location: Shropshire
Great Britain

#2 Re: Prop shaft doesn't fit through the tunnel!!??

Post by Series1 Stu » Mon Apr 15, 2024 11:04 pm

Hi Andy, I feel your pain.

It looks like some half asleep drone working for said "specialist" has rounded 3.75 inches up to 100mm without considering the possible effects. Happens all the time in this game. Our cars were made under the Imperial system, so, please suppliers, stop using metric measurements.

I know it's not the point, but I wonder if it would have fit from the other direction.

Unfortunately, this stuff happens when someone gets hold of a set of Vernier calipers and then think they're an engineer. :banghead:

Going for a lie down in a darkened room now.

Regards
Stuart

If you can't make it work, make it complicated!

'62 FHC - Nearing completion
'69 Daimler 420 Sovereign
'78 Land Rover Series 3 109

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

lowact
Posts: 627
Joined: Mon Oct 09, 2017 10:05 am
Location: Canberra, Australia
Contact:
Australia

#3 Re: Prop shaft doesn't fit through the tunnel!!??

Post by lowact » Tue Apr 16, 2024 10:30 am

I would not expect changing the flanges would affect the balance, which is mainly to correct the fabricated shaft. Was the new one sold as having been balanced, are there balance weights?
Regards,
ColinL
'72 OTS manual V12

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

Mich7920
Posts: 757
Joined: Sun Mar 15, 2015 4:43 pm
Location: France
France

#4 Re: Prop shaft doesn't fit through the tunnel!!??

Post by Mich7920 » Tue Apr 16, 2024 12:11 pm

Hi Andy,
why not correct or have the diameter corrected on a lathe?
You'd have a better chance of keeping it completely balanced.
If it really is balanced, changing the flange will damage it.
Mich
Michel
1965 E Type FHC - On the road / 1963 E Type OTS - on the road after Angus Restoration

Link:
BBcode:
HTML:
Hide post links
Show post links

Post Reply Previous topicNext topic