what size bolts for spring hangers to replace rivets? and part #for shorter shock?
 

I'm going to be lowering my truck next weekend so I'm trying to have everything I can lined up for me to do so. I'm going to be raising my stock spring shackle and hanger brackets 3-4 inches and drilling new holes on the frame I need to know what size the rivet hole is so I can have the bolts ready on hand as I do all my crap outside by myself so I'd like to have it ready to go. Also does anyone have a part number for a 3 or 4 inch shorter shock? My truck is a 1980 c20 thanks in advance.

Re: what size bolts for spring hangers to replace rivets? and part #for shorter shock
 

3\8 x 1in coarse thread grade 8.

EDIT: Thats the bolt size I used on my c10.

Re: what size bolts for spring hangers to replace rivets? and part #for shorter shock
 

some have used the 7/16" also.

Re: what size bolts for spring hangers to replace rivets? and part #for shorter shock
 

3/8" will work, but they are usually a bit smaller than the rivet holes. I would go with the 7/16" grade 8's and drill the holes.

Re: what size bolts for spring hangers to replace rivets? and part #for shorter shock
 

The rivets are probably the equal of grade 8, and they don't have threads cut in them. (Compare bolt minor diameter) When I had to remove an reattach the hangers on my 77, I used 1/2". Figured what the hell, and there was plenty of metal in the hanger to accommodate the larger hole. Well, it's been like that for 15 years now.

Re: what size bolts for spring hangers to replace rivets? and part #for shorter shock
 

It is my understanding that the rivets used in the chassis are grade 5 . They have to be a softer grade in order to crush properly .

Re: what size bolts for spring hangers to replace rivets? and part #for shorter shock
 

I just finished replacing all of the rivets in the rear of my frame after sandblasting last week. I used 1" long 7/16 grade 8 flange bolts, torqued them to 77ft/lbs with lots of red locktight. rivets are grade 5, but I used grade 8 because I am not looking for flex, Im looking for rigidity and stiffness.
flangebolts.com was where I bought them.

Re: what size bolts for spring hangers to replace rivets? and part #for shorter shock
 

I was interested in finding out more, and discovered the following article:
http://www.tech-cor.com/AutoResBulle...0-6/2000-6.htm
Now, this is for a ford f-150, but it gives factory recommendations on rivet replacement. Near the bottom if you don't want to read the whole thing.

Re: what size bolts for spring hangers to replace rivets? and part #for shorter shock
 

3/8" grade 8 bolts were the assembly line repair for missing or miss hit rivets for our trucks.

Mine is going on 29 years and 200,000 miles with bolted on spring hangers.

K

Re: what size bolts for spring hangers to replace rivets? and part #for shorter shock
 

Thanks Keith. I guess I'm not surprised, since a 3/8 grade 8 can take nearly 10,000 lbs in shear. https://nucor-fastener.com/Files/PDF...r_Strength.pdf