Front spring U bolts

[Howard Wright]

Hi All

Thanks for the responses.  If I can summarise 

There seems to be no mechanical reason why u bolts are used over bolts and plates however they do form a light and neat solution and as far as initial manufacture (or with the engine out) are easy to install.

Bob’s comment about a plate stiffening the spring to the extent of snapping the spring may be possible but will depend on the extent and shape of the plate.

The reason for the original question is that having installed a bowed front axle and finding that it provides too little ground clearance for trialing I am constructing a “trials” front end that can be swapped over late summer for the season and back in spring for road use. The only bolts to undo are the spring, radius arm ball, brakes shock mounts and steering arm. Of these it is the spring bolt under the cam pulley that is the most difficult. However it is not that difficult so I will probably stick with u bolts.

Thanks for all the help 

Cheers

Howard

[dickie65]

Modern boat trailers still use U bolts to secure various parts together. So they still have their place.

[Davemayle]

Hi Howard, I read your last post with interest as I have just replaced a straight axle with a bowed axle & flat spring. I had to remove the radiator and surround to gain access to the U bolts. My thoughts were inline with yours being able to swap back easily. A few other problems like the drag link now hitting mudguard stays to overcome...

[Howard Wright]

Hi Dave

I can get to all the bolts but the one under the fan pully needs a short ring spanner and lots of patience.  I've remodelled the flitch plate to accommodate the drag link three times now!

I think the front ends (bowed and straight) will include everything including wheels.  In that way you can push it under the car and drop the chassis onto the spring then lift the radius arms to fit the ball bolt.  I've assembled a straight axle, swivels, hubs, brakes and already its just too heavy to lug around.

Good luck!

Cheers

Howard

[Ivangardiner]

My American Bantam did not use U bolts on the front spring. It used 4 bolts and a specially cast (or forged) clamping plate.  As originally produced, the radiator had a bottom bracket which was held by 2 of the said bolts.  Don't tell any of the US purists this, but I modified things so it was no longer necessary to remove the spring bolts in order to remove the radiator .  The nose-piece of the chassis was EXACTLY the same as on a seven of about 1930, including the threaded holes (unused)  for the A7 "cow horns".
Useless information?  Oh, well...

Ivan

[AustinWood]

U bolts are a sound and simple fixing. I doubt whether changing the front axle assembly was on the list of design requirements.

[Dave Wortley]

On my Cheapskate special I made a top plate from a gib head key I “found” at work ( big one from steelworks equipment) The hole in the floor was a slot which allowed access for quick removal. The bolts were something like 3/8 high tensile from my collection. Bottom plate was standard A7 I think. Cost nothing. Rear spring u bolts were not available at that time.