Trailer bolts

[ovakil]

I'm replacing all u bolts on axles & was looking at replacing the bolts which hold the leaf spring to chassis.When I took out one of those bolts to get a size,I saw they not a standard bolt.The head (fits 17mm spanner) has an internal hole(approx 6mm dia) with a thread that runs about 30mm into bolt then a small hole at right angle through side of bolt.
Is this hole for putting grease into bush?
I had to clean bolt to see holes,should they be cleaned out regulary?
Thanks

[finga]

yep.
There should be a grease nipple there as well to pump the grease in with

[ovakil]

The internal thread must be for grease nipple as there aren't any there.Should all the bolts have nipples ? Or do you screw one on,grease it then do the next? What is best way of cleaning bolt out? Prefer not to take bolt out.Can you use wheel bearing grease? As I only have one grease gun.
Thanks

[gone_fishing]

ovakil
there called shakle pins and the type you desribed should have grease nippples in them use a oil based chassis grease can use wheel bearing grease if thats all you got
now you got one out check for wear if the pin is out of round
there also should be a bush inside spring eye most are made of plastic pin and bush should be a snug fit might be worth replacing
they dont need to be cleaned as such just a squirt of grease will do the job
you should be able to get them at any trailer shop

hope this hellps all the best

[Eagle]

I worked last year with a major spring manufacturer. I did all the design drawings with CAD for dozens of leaf springs, shackle pins, U bolts, spring washers, nuts and everything else related to running gear.
The small hole in the end of the shackle pin should have a grease nipple screwed into it. The size of the thread is 1/8 BSPT. Most of the s/pins have a small flat where the small exit hole is on the side of the s/pin. The flat/s are to ensure the grease can spread along the surface of the s/pin and spread over the interior of the bush. Some had the hole passing completely thru the s/pin and a flat on both sides. The grease nipple must be retained in the end of the bolt. This is to lubricate the s/pin at all times.The nipple also keeps water and crud out of the pin (does help). A good water resistant chassis grease is best but any grease will do the job if nothing else is available.
Where a spring washer is used, make SURE the internal diameter is not sloppy on the bolt. Many of the imported assemblies from India have washers that are far too big in the i.d. This results in the nut squashing the washer open and the nut is no longer seated on the spring washer whatsoever and the spring washer no longer has any "locking" properties.
When assembling the shackle pin and spring/bush, the flats should be located on the side/s of the s/pin. This presents maximum bearing area of the top and bottom of the s/pin and bush to take the loads.

Eagle

[ovakil]

Had a look at the s/pin I took out the thread for nipple looks a bit on the worn side.By the looks they have never had nipples on them.Trailer is 97 model.Going to buy new s/pins with nipples as I'm replacing most bolts,as I would hate to think what would happen if one would let go on highway.
Thanks

[ovakil]

Went down to trailer shop today & the guy told me that I was wasting my time buying bolts with the grease nipples.Still bought them as I said can't do any harm keeping bolts greased up.
Cheers.