Community Forums

FFG · 08-16-2019, 06:33 AM

Filed the MoT this morning on brakes efficiency (which I can sort) and one of the u bolts on the rear leaf springs has broken. So i need to replace the u bolts and get the garage to look at the brakes so does anyone have the spec of them. Its a P30 chassis - 1995. Nothing coming up on the shelf here in the UK, so trying to avoid shipping and customs costs.
FFG

RickNC · 08-16-2019, 02:41 PM

Quote:

Originally Posted by FFG

Filed the MoT this morning on brakes efficiency (which I can sort) and one of the u bolts on the rear leaf springs has broken. So i need to replace the u bolts and get the garage to look at the brakes so does anyone have the spec of them. Its a P30 chassis - 1995. Nothing coming up on the shelf here in the UK, so trying to avoid shipping and customs costs.
FFG

5/8" diameter fine thread x 2.5" inside width. SAE Grade 5 or 8 hardness/strength. Length will vary depending on height of spring stack and spacers.

leadman · 08-16-2019, 03:01 PM

Go to a spring shop that does suspension work and they can probably make you one easily. Most of the u-bolts I have installed over the 50 years were made this way. I would have 2 made and replace the broken one then the other one. Torque the nuts evenly and retorque after you have driven it a bit.

FFG · 08-17-2019, 01:14 AM

Thanks. I'll measure them today as it was lashing down all day here yesterday. I'll get 4 as I'll replace the ones on the other side too given they're all the same age and been under the same stress.
FFG

FFG · 08-18-2019, 11:48 PM

Its 10" long from the underside to the end and it is 2.5" wide and 5/8" diameter bar. I'll see if I can find any suppliers in the UK.
I'm going to replace all 4 now.
Many thanks.
FFG

FFG · 08-23-2019, 03:26 AM

I can get a 5/8" socket on the thread so looking at this site the bar should be thinner than the socket that fits but doesn't list a 5/8" socket?
https://www.generalspringkc.com/product_p/u%20bolts.htm

They also seem to be near 2.5" wide nearer the bottom but at the top oif the leaf spring they seem to be slightly wider - maybe 2 9/16". I can see some markings on the leaf spring, EC4-259 biut can't find any reference to it.

I've tried to source some in the UK but I'm not happy that the steel spec matches SAE5 or 8 so I'm going to get from the US. Prices aren't that much more even adding shipping and customs charges.

FFG

leadman · 08-23-2019, 06:56 AM

You need to measure with a caliper if you have one. If not do the best you can with a ruler. Putting a socket on the threads will not give you an accurate reading.
The letters on the spring were from the original manufacturer that supplied the parts to the chassis builder and probably won't help you much.

The parts you can get locally should be ok as they have been building vehicles in the UK for a long time. Can't tell you off hand what the spec should be but I would not hesitate to use them.
My concern is where does the company get the parts from here in the USA? So much of our stuff is coming from China and most of it is questionable.

I recently installed 2 upper control arms on my truck that were MOOG parts, normally top quality parts. Turns out they were made in China and in 6 months the rubber ball joint boots were cracked and leaking grease. Moog gave me another set made in Taiwan! We'll see how long these last.

FFG · 09-21-2019, 09:12 AM

Bought from Stengel bros in the end as I wasn’t happy with the Uk steel specs being offered. Cost $42 plus around $110 to ship and customs fees but they are the right spec and fit perfectly so I’m happy. I’ve torqued up to 70 ft lb but do I really need to be up at 150 ish?

RickNC · 09-21-2019, 10:24 AM

Quote:

Originally Posted by FFG

Bought from Stengel bros in the end as I wasn’t happy with the Uk steel specs being offered. Cost $42 plus around $110 to ship and customs fees but they are the right spec and fit perfectly so I’m happy. I’ve torqued up to 70 ft lb but do I really need to be up at 150 ish?

Yeah you kinda need to. It wasn't fun for me when I did them. I have a click type torque wrench so I slipped a section of metal fence post over it for leverage. You also need to re tighten after a hundred miles or so.

FFG · 09-21-2019, 11:03 AM

My wrench maxes out at 150 so been looking at a 300+ one. Bid on one last night but didn’t get it. Teng but it’s 33in long.

leadman · 09-21-2019, 10:05 PM

Don't overtorque them as this can lead to breakage as they stretch a bit when torqued.
The advise to retorque is a common and sound practice when replacing the u-bolts. If the u-bolts loosen the center bolt in the leaf springs can break and allow the axle to shift. Something to avoid.

FFG · 09-22-2019, 06:38 AM

Chassis manual states 125-175 but I'm sure I read somewhere if you put any ant seize compound (I've used copperslip) a figure in the middle is acceptable, ie where I got the 150 from. Is this correct?

leadman · 09-23-2019, 08:45 AM

I have never put antiseize on u-bolt threads. It can change how much the bolt is stretched as it reduces the turning force of the nut. This can cause the bolt to be stretched too much and it can fail.
This is just like the wheel studs, torque value given is with them dry, no oil, no antiseize.

I had a Supervisor that did not believe in replacing the u-bolts, even when I showed him in the trucks repair manual. About a month later I had one break just as I reached the #500 torque on the nut. Unfortunately I had my hand under the head of the wrench holding it in place and it slammed my hand into the dirt and gravel on the floor. Still have depressions in the bones in that hand.
We got new u-bolts after that.

FFG · 09-23-2019, 11:01 AM

Its on now so I'll have to live wit hit. If they fail I'll buy another set and learn my lesson. I use it on everything but maybe need a re-think given the high torque figures involved. This is a site which mentions a torque figure in between the 2.
https://www.autoandtrucksprings.com/...-u-bolt-torque