1986 Chevy C10 SWB Step Side

[aotte1]

Doing research on front suspension rebuild, following info from Moog-Problem Solver Coil Spring Catalog June 2009,:

They list three springs for 1973 to 1987 trucks, etc;

Number "6252" - C10, c1500,r10 for 91 to 73, also for c20 and c30 for [81-77]{ NOTE: these are generalizations of applications- their was a page of specific applications, so need to check book for specific models/options}

Number "6254" as Heavy Duty - same as above models and years except C30 is for 91 to73 for this spring.

Number 6560 for C30 -F42 and 6560S as super duty, and F42 for years 1982 to 1987 (It is also used for later year trucks too)

Coil Spring Specifications:

6252- inside dia =3.680 in., bar dia =.781 in., installed height = 10.00 in., load = 3156 Lbs., spring rate = 843 lbs/in, free height = 13.64 in.

6254- inside dia =3.676 in., bar dia =.828 in., installed height = 10.00 in., load = 3841 Lbs., spring rate = 1060 lbs/in, free height = 13.61 in.

6560- inside dia =3.650in., bar dia =.906 in., installed height = 11.00 in., load = 3289 Lbs., spring rate = 1501 lbs/in, free height = 13.19 in.

6560S- inside dia =3.650 in., bar dia =.906 in., installed height = 11.00 in., load = 3788 Lbs., spring rate = 1464 lbs/in, free height = 13.591 in.

Note: some of the specs for 6560 and 6560S, spring rate look a little odd, would call to confirm numbers if interested in using.

Will try to check Master GM Truck Parts Catalog to see if they list spring rates for OEM springs for reference.

[SkinnyG]

Originally Posted by aotte1

One side had at least .75", however the other side only had .57".

I drilled mine 0.75", and beat this area of the cross member to clear (I'm not one for originality):

[aotte1]

SkinnyG,

Thanks for the info and pictures on how you made your clearance. Great idea too.

[aotte1]

Continuing to work on R/R of the front suspension, worked on the upper and lower control arms. First removed the lower ball joint by pressing them out, them came out easy. The removal of the upper ball joints was another story. First cut the rivets heads off both sides, then tried to knock them out with hammer and punch, them would not move any. Next tried air hammer with chisel, any they would not move. Tried 5 lbs hammer hitting ball joint, again they would not move. Last option, heavy weight strong machinist swinging control and hitting ball joint against anvil many times, finally they started to release. Probably hit them about 20 times to get them out.

After removing ball joints cleaned them with solvent, followed by blast cabinet. The cabinet worked very well, used alu oxide 120 grit. They were then coated with ceramic coating per process mentioned above. The next step is to install the replaceable parts for the uppers and lowers

[aotte1]

Another picture of upper control arm.

[aotte1]

Upper other side

[aotte1]

Another picture

[aotte1]

Lower control arm picture

[aotte1]

Lower close-up

[aotte1]

The other side lower

[aotte1]

The upper and lower control arm shafts

[aotte1]

The lower control arm shafts with caster mod of 3/4 inch.

[aotte1]

Also, cleaned, blasted, and painted the crossmember today.

[aotte1]

Another view of crossmember

[aotte1]

A few pictures of the OEM spindles, planning to use them, and cut one coil off original front springs as a starting place on lowering truck a little. Will put it all back together and see how the 2 inch drop from cutting one coil, looks. My decision was based on the different impacts of drop spindles vs cutting one spring coil. The cut one coil option provided the following benefits: 1). Can use 8x15 inch wheels and more then 3.5" of back spacing (BS) ( max amount suggested if using drop spindles, also narrower wheels recommended in the 6 to 7 inch range including smaller tires). I plan to use 8 x 15 wheels with 4 to 4.5 inch BS and 275x60x15 tires. 2). The suspension geometry is minimally effected. and 3). Less issues of truck bottoming out on bumps, along with headers dragging. This is my first time doing this to the truck and decision is based on help from many members, along with their posts here.
Will continue to report as I put it back together.
Les

[aotte1]

Couple more spindle pics

[aotte1]

Close-up

[aotte1]

The other side

[aotte1]

The Moog suspension parts being using. I decided not to use the offset upper control arm shafts, after talking to my alignment person. Will use original upper cross shafts as starting point for initial set-up of suspension. Goal is zero to minus 1 degree camber.

Parts are at machine shop friend getting put together.
Les

[aotte1]

Weekly body shop report no progress last week, should be back working on it this week.
Getting ready to cut front spring soon, will cut them on bottom, at angle so that the cut will sit flush in lower control arm. It will be a pain, however do want to add twist to them because they are not sitting flat in control arm.

Also researching parts needed for interior.
Les

[SkinnyG]

Do you mean the offset ~lower~ control arm shafts? What did your alignment guy say? (If you don't mind my asking)

[aotte1]

SkinnyG,
Yes, moving the lower control arm forward 3/4 inch. Alignment person ( Joe)has worked at same Michelin tire shop for 35 years doing alignments, I have used them for 12 years, just a little background, that I believe he know how to do alignment requested if not factory spec.
Joe agreed that increasing caster was a good idea for wide front tires on old trucks like the 1986 C10. His thoughts were that, 4 or more degrees would be helpful in keeping truck from trying to follow every imperfection in road at highway speeds. He emphasized that having 4 degrees would help a lot. With slight negative caster also, he could make it drive nice by adjusting toe. He also asked how many rear shims it had before changes, because caster adjustment via shims is made by moving upper control arm out, and you run out of bolt length to do very much caster increase.

With all the changes I am making, Joe said I could adjust camber at home before bringing in for alignment with level on side of tire to get it a little negative. He also told me how to get truck tires sitting neutral for checking camber, role it back and forth several times.

Overall he thought it was a good thing to do, and changes in front spring alignment of 3/4 inch was no big deal.

Thinks that's pretty much what he said, will be few months before I report back on how it drives ( truck is in body shop .......limbo) actually thick truck is doing well, for all the quality work they are doing!! Taking their time to do it right, with a few other small jobs being done along the way, as needed for his business.
Les

[SkinnyG]

Since you are lowering via springs, you will automatically gain some negative camber (tires tipping inward at the top). For a street vehicle you probably want to stay around -1° camber for best tire wear. This likely will be able to be corrected by adding shims to the upper control arm to move it outward.

Caster (angle of the steering axis through both ball joints as viewed from the side, the steering axis should intersect the ground ahead of the centerline of the wheel - think of "caster wheels" with the pivot always ahead of the wheel) is increased by adding shims in the front and removing shims from the back - this moves the upper ball joint back. It is possible that you will not be able to get enough shims in the front to maintain acceptable camber and yet still reach your caster goal.

Alternatively, you could move the lower control arm forward (moving the lower ball joint forward does the same thing as moving the upper ball joint back). This should allow the caster to be increased, while leaving majority of the shims to correct the camber.

One quirk I found, was the springs were more difficult to install with the lower spring basket moved forward.

[aotte1]

Today finished putting the upper and lower control arms together. They went together pretty easy. Just FYI, the hardware for the uppers was one gold Cadmium and the other black. The R/R of the control arms include the lower control arm modification to add more caster. The change I made will move the lower arm 3/4 inch forward. This amount seems to be a common dimension reported here by many. Plan to install the control arms on the cross members soon and see how much clearance I need to add on the cross member for full travel. Today also prepared the hardware for installing the lower control arm. Will report back w/ more pictures.

[aotte1]

The other side of the upper control arm