Author Topic: Inch Thread in Power Steering Pump - Please Kindly Verify What I Found  (Read 264 times)

Pawel66

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I have a kind request to verify: the thread in the bolt holding the PS pump to bracket (the one protruding through pump housing) is 3/8 UNF. Spanner 14mm fits, but the bolt is 3/8 inch.

This is what I could find on the forum. Is it correct?

I checked and it fits 9.5mm thread, so I hope it is correct.

Any hints where to source this bolt? EPC does not help....
Pawel

280SL 1970 automatic 180G Silver
W128 220SE
W121 190SL
G-class

WRe

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Pawel66

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WRe, thank you!

I had good 6 pages of hits on search, I have no idea why I have not come across these posts... thanks again!
Pawel

280SL 1970 automatic 180G Silver
W128 220SE
W121 190SL
G-class

Pawel66

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I had to change this post.

Here is what happened: someone sometime screwed in UNF bolt while the pump housing had UNC threads. That is how the screw/thread got destroyed.

I cleaned the threaded orifice tonight and the thread that emerged was UNC thread and it fitted UNC bolt. I need to buy a tap or heli coil and fix the thread in the housing. But UNC it is.
« Last Edit: January 20, 2022, 21:03:11 by Pawel66 »
Pawel

280SL 1970 automatic 180G Silver
W128 220SE
W121 190SL
G-class

Kevkeller

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Can you use a rethreader?  It’s like a tap but straightens out damaged threads instead of cutting new ones.
1970 280 SL

Pawel66

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Thank you for the thought, but I am not sure if I am familiar with how it looks like.... sorry for my ignorance...

Sounds useful. Will look for it.
Pawel

280SL 1970 automatic 180G Silver
W128 220SE
W121 190SL
G-class

MikeSimon

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If you are not a stickler for originality, I would drill and retap the hole and insert a metric thread coil. Will make it easier to replace hardware in the future.
The reason some hardware on the p/s pump is odd, is that it is based on a Vickers US-model VT27/VTM42 power steering pump and some dimensions and specs were taken over unchanged.
1970/71 280SL Automatic
Sandy Beige
Parchment Leather
Power Steering
Automatic
Hardtop
Heated Tinted Rear Window
German specs
3rd owner

Pawel66

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Yes, crossed my mind, thank you. I thought M10 would be my last resort.
Pawel

280SL 1970 automatic 180G Silver
W128 220SE
W121 190SL
G-class