AC DELCO TYPE MECHANICAL PUMP - looking for replacement screws

[Top Banana]

All,

I am looking to refurbish my very tired fuel pump see attached photo, the screws heads are damaged the previous owner(s) seem to use one size of flat screw driver regardless the size of the screw head size.

Does anyone know where I can buy replacements or the size / thread of these screws

Also, once I know the thread size I am tempted to replace flat heads with Allen key screws, would this be considered sacrilege from a car authenticity and valuation view point. 

I am thinking of going for the ANG fuel pump repair kit that Ethonol friendly, I just looking for a quality product.

Thank you

[Colin Lindsay]

Amazingly (to me!) they're metric, I make it about M4 size and 2cm long.

[Chris A]

27 minutes ago, Colin Lindsay said:

about M4

Precision measurement again Colin 😁

Looking at those screw heads the same person, with same screwdriver, must have replaced the petrol sender unit on my 13/60 at some time in the past. 

[Colin Lindsay]

8 minutes ago, Chris A said:

Precision measurement again Colin 😁

Looking at those screw heads the same person, with same screwdriver, must have replaced the petrol sender unit on my 13/60 at some time in the past. 

I didn't have a spanner that went down so small..... but they're slightly smaller than a size 5.

Definitely not UNF.

[Pete Lewis]

part number is 52409   not in the triumph hardware catalogue  &  not available at most outlets 

i would be suprised AC used any metric threads  but  we like surprises 

been looking at SU float lids and piston cover screws but cant get the sizes being of the same era 

pete

[Chris A]

14 minutes ago, Colin Lindsay said:

didn't have a spanner that went down so small..... but they're slightly smaller than a size 5.

My method would be, undo one of the screws, take it to my 'stock room' and rummage in my box of spare nuts until I found one that fitted. Then use that nut and rummage in my box of left over bolts until I found one that matched, then try and find enough to replace all the screws . . I'm retired so I have plenty of time for this type of thing 😵

The heat is getting to me. 😎

[Colin Lindsay]

2 minutes ago, Pete Lewis said:

part number is 52409   not in the triumph hardware catalogue  &  not available at most outlets 

i would be suprised AC used any metric threads  but  we like surprises 

pete

Always happy to be corrected provided it hasn't caused anyone else either expense or bother!

Same method as Chris: I took one screw out of two NOS pumps, tried a selection of nuts from various boxes and they didn't fit a UNF nut, but a metric M4 nut screwed on each fitted perfectly on both. Unless there's an Imperial screw with the same threads? I have the 1973 AC catalogue but it only lists exchange units, not spares.

 

 

[68vitesse]

Think they are No10 UNF Fillister head machine screws same thread as the door handle machine screws, the one by the quarter light, if you want to check the thread.

This sort but check.

 3/16" (10-32) UNF 3/8" to 1" A2 STAINLESS STEEL SLOTTED FILLISTER SCREW x 10 | eBay

Regards

Paul.

[Pete Lewis]

think thats good enough  well   ACD was part of GM so its possible isnt it ???

they were just down the road in Dunstable   you could knock em up 

but its all gone and just a  block of houses and flats now ..

 

i  would have thought that but No10 is 0.190" which is heading for 5mm Od.

no 8 is smaller at0,164"

4mm is 0,157"   ?????????????

 

Pete

 

[Colin Lindsay]

https://www.flexolite.co.uk/categories/flexolite-fuel-pumps-repair-kits-regulators-and-filters-repair-components-for-ac-fuel-pumps

Ok try No6 x 32 UNC. I can at least try to redeem myself....

[Pete Lewis]

redeem  NO      not yet  scroll down theres  No10s and M5    they are breeding 

thats a good site  worth putting on file 

Pete

[Wagger]

I'll go with that Colin. I think?

UNF should be Unified Fine. They are too coarse for that. Could be Unified Coarse (UNC). My guess is that they are BSW (Whitworth) coinciding with a metric. They have been around a while so should not be metric.

Where are my gauges and flaming Zus book again? I do have a set of small BSW dies. (Do I?)

I've been around too long. BSF and BSW had different size heads when I started. Then we had 'Auto-head' which made them the same size. Then A/F imperial, then A/F metric. I've started, so I'll finish. They are definitely not BA!

 

[NonMember]

1 hour ago, Colin Lindsay said:

Ok try No6 x 32 UNC.

I didn't think they were that small. 6-32 is a standard thread for computers - mounting bolts for 3.5" hard drives, for example.

[Colin Lindsay]

Does that look like the right one? Found it on the link above, I'm having one of those days where it gets worse, rather than better...  Desperately digging but the hole is getting deeper...

[68vitesse]

Think the clue is in valve retaining plate used on early fuel pumps before the valves were held in by punch marks.

Regards.

Paul.

 

[Gully]

I reckon there's another 50 years left in the original screws! 😄

Gully

[Top Banana]

All,

I will order an assortment of sizes No 6,8 unf and research the link to the flexolite.co.uk. Having looked at the threads of the removed screws on the pump they look very fine (UNF / metric like). Searching through my old tin of screws and nuts, I could not match anything sensible. 10-32 unf is too large. Nothing Metric fitted, but I was able to screw in with a little pressure the "Philips screw" for a Stromberg CD150 that holds the float chamber in place (bought these screws from James Paddock, but the size/thread is not published). I am now contemplating that the existing screws may not be correct since they are slightly loose within the threads the body material seems very soft and that some of the threaded holes are not in fact verticle to the eye (hey ho!). Anyway new screws will go in with a little loctite to steady the ship !

So what I need is the equivalent of a "Jamboree bag" of screws; for those that may be a little young for the reference follow the link below.

https://www.doyouremember.co.uk/memory/jamboree-bags

Will report back my progress

thank you 

John

[Chris A]

1 hour ago, Top Banana said:

for those that may be a little young for the reference follow the link below.

I must be one of those a little young as I know them as Lucky bags.