Differences in front subframe bolts/ studs

[mr-marcos]

When I was taking apart my last project I noticed it was using studs to to hold the subframe in (solid mounted pre 76). The interwebs sheded some light on the subject but very unclear. Is it known what was used on what sort of car? This is a dry subframe and must be pretty early as the car was build up using steel trumpets on the front and rear subframes. Later on the fronts were swaped for Tony Chaming hi-lo's. I am used to using the bolts with lock tabs under it. Otherwise I would reproduce a set for my car.

[Daz1968]

I am not sure of change date but early cars have stud and nuts, you cannot use the bolts in these frames as the thread size if different. My 1962 has studs whereas a 1966 front subframe I have has the nuts,
When I restored mine I couldn't find any replacement studs but I have since seen them for sale on the swift tune site

http://www.swiftune.com/Product/880/swi ... d-kit.aspx

[mr-marcos]

Interesting to know why there is are 2 types. I found the swiftune ones but not going to pay 48 pounds for 4 studs as they are different as well, I want to have the original rounded off heads. I have made loads of stuff and in the very near feature I will have my lathe and make them myself out of C45, 42CrMo4 or something similair. But is it specific to certain production years or is it morris vs austin? It seems that it's not an hydro subframe.

[johnv]

I had the same question .
http://www.theminiforum.co.uk/forums/to ... try3444537

[Spider]

I think the early cars were 5/16" UNF and later were definitely 3/8" UNF.

I make the subframe studs from Long Head Studs.

[smithyrc30]

The hydro cars are bolts, not studs.

Well all the ones I have worked on anyway.

They are 3/8"UNF and are wasted down to 5/16" diameter just below the head (about 3mm or so from the bolt head face).

As already stated the early cars were 5/16"UNF late 3/8"UNF.

If BMC was a logical company the change would have been around the time hydro was introduced but....

[johnv]

like I said on the TMF post .. mine's hydro and studs ...

[Spider]

What's wrong with this 'picture'?

If BMC was a logical company,,,,,,,,,,

OK,,,, OK,,,,,, Yes, you did say 'If',,,,,,

[mr-marcos]

What I think is that they used studs at first because it is much easier to put a subframe with the studs in directly into the right place than with bolts. With bolts there is a possibility that you will need to mangle the subframe around to get the bolt threaded in. On the website of Somerford is some info on it. This is what they have to say:

Models up to 1962 approximately (i.e . those with the very earliest types of dash crossmember) could have the subframe towers held to the dash crossmember by bolts or studs and lock tabs which initially didn’t, and then did, allow access to the rubber cone compression nuts. After this time bolts were used exclusively on cone (dry) suspension cars. Hydrolastic (wet) suspension subframes were also held to the dash crossmember by a choice of bolts or studs. The only real consistency is that bolts were always used on the subframe towers on the Cooper and Cooper S. Fixings are interchangeable so long as complete sets are used, but cone type fixings should not be used on Hydrolastic cars, nor vice versa.

There are also 2 different part numbers on there for the studs;
* Tower Studs, 1959-62 Approx. (cone suspension; alternative to bolts)
28 21A499 STUD, subframe tower to dash crossmember
* Tower Studs, 1964-71 (Hydrolastic suspension)
37 53K1483 STUD, subframe tower to dash crossmember

Funny enough the nuts have the same number so must be equal. This can point out that there are 2 diffent threads on the subframe side as earlier mentioned...

[whistler]

The hydro cars are bolts, not studs.

Well all the ones I have worked on anyway.

They are 3/8"UNF and are wasted down to 5/16" diameter just below the head (about 3mm or so from the bolt head face).

As already stated the early cars were 5/16"UNF late 3/8"UNF.

If BMC was a logical company the change would have been around the time hydro was introduced but....

My Morris 66 hydro SDL uses studs with 5/16" studs. I believe the Austin version used bolts; go figure that one out.

[Toby]

I was just thinking, it doesn't make any sense that BMC would go to the lengths of producing two kinds of front subframe with different thread sizes. It's just not practical.

So could it be that people might have had their studs the wrong way round when they tried to fit them? As they have diffferent threads either side of the stud.

Stud were used up to about 62 after which bolts were deemed as the standard.

[whistler]

I was just thinking, it doesn't make any sense that BMC would go to the lengths of producing two kinds of front subframe with different thread sizes. It's just not practical.

So could it be that people might have had their studs the wrong way round when they tried to fit them? As they have different threads either side of the stud.

Stud were used up to about 62 after which bolts were deemed as the standard.

As far as I know the dry bolts/studs had 3/8" UNF thread going into the tower with 5/16"UNF nuts on the top. My Hydro has 5/16" UNF on both ends. Maybe the reason is that the Hydro subframe bolts directly to the bulkhead crossbeam whereas the dry one has a spacer.

[Toby]

Reading back I guess I might have been unclear. I was refering to the dry front subframes.