Front and rear suspension trumpet lengths ???

[jaknight]

I am seeking the original lengths of the front and rear trumpets for the suspension.

According to what I have read on this forum, I should have cast aluminum trumpets. However, I have cast aluminum on the front and steel on the rear. So, these have been changed over the years.

The car is a 1965 Cooper S that is undergoing a restoration.

The front aluminum trumpets measure 3 1/4" long from the wide flange ( 3.275" diameter ) for the rubber cone seat to the end of trumpet for the knuckle joint.

The rear trumpets are steel and are 12 1/4" long from the wide flange ( 3.260" diameter ) for the rubber cone seat to the end of trumpet for the knuckle joint.

I do not know the part number of the trumpets as these have been powder coated.

Currently the vehicle is on a rotisserie and upside down. I have installed the rear trumpets and rubber cones along with a 10" wheel and tire and this gives approximately 9 inches of clearance
from the tire to the wheel well lip. I know the rubber cone will settle some when the vehicle is on the ground with weight on it. That seems like a lot to settle / compress ??

What amount of clearance should I expect for the front and rear ... tire to wheel well lip when the vehicle is fully finished ??

Thanks for your help.

Jim

[Spider]

I don't have an references to the steel trumpets, however, from memory, they were phased out in 60 or 61.

The stock Alloy Front Trumpet, P/N 21A530, flange dia 3.235", active length 3.370"

Mini Saloon Rear Trumpet, up to 86, P/N 21A1683, flange dia 3.200", active length 12.287"

Mini Van, Big Wheel Moke and Mini Saloon from 86 on, P/N 21A1684, flange dia 3.700", active length 12.402"

In regards to the 'ride height' you currently have, is the car completely fitted out, with all trim, glass, boot lid, engine etc? Until it is, ignore the suspension, after which, it will settle (depending on the brand of the rubber cones),

[jaknight]

Spider ,
Thanks for the reply. I continue to learn regarding the many parts and change overs through out the years of Mini production.

Currently, the car only has the rear subframe and components on the body and is attached to the rotisserie.

Should all trumpets have part numbers on them?

Jim

[Spider]

Hey Jim,

OK, in regards to ride height then, it's too early to make a call on that with your project. They always come off the stands looking way too high, so don't be alarmed at that, give it about 2 - 4 weeks.

The Front Alloy Trumpet, P/N 21A530 was a direct replacement for the steel ones (P/N 2A4355) that preceded them and was the same one used right up to the end of production. I've not found any P/N's on these.

The Rear Alloy Trumpets, P/Ns 21A1683 and 21A1684 do generally have visible part numbers, up near the flange



I do note though, that there was 2 other Rear Alloy Trumpets unique to the Cooper and Cooper S, P/N for the Cooper type 21A1031 and for the Cooper S 21A1302. Additionally, the Steel Cooper type was P/N 2A7375. Other than P/Ns, I have no other reference to these unique Cooper and Cooper S Trumpets, so I don't know what flange sizes they had nor what the lengths were, I'm sorry, however, given the flange diameters of the Rears you have, I'd say they could be of one of these types.

[NickD]

Some further info regarding the trumpets fitted to to Cooper & S models as mentioned by Spider:
21A1031 was the standard alloy trumpet fitted to Mk1 850s and Coopers up to the introduction of hydrolastic suspension. This had the small 3.25" flange and shorter length, and was replaced by the similar 21A1683 when dry suspension was reintroduced.
21A1302 was only fitted to Mk1 Cooper S models until September 1964. This trumpet had a large 3.7" flange (as on the later 21A1684) but was the same length as the 21A1031 trumpet.

[1071bob]

Just to confuse the issue there is a batch of large 3.7" flange trumpets with 21A 1032 cast into them. This could be a mistake by the foundry people getting the numbers mixed up because there are other large flange trumpets with the cast part number ground off and the correct 21A 1302 number stamped in. The length is the same @ 12.3 inches.
Thanks to Dermott and Chris in NZ for supplying info on this.