The Stovebolt Site Forums The Shop Area Driveline R&R rear springs, '50, 3604

Well howdy do boys, been a year or so since I’ve posted anything due to a ton of
various other things that have taken priority.
Haven’t driven or worked on Old Blue since last fall because of my shattered right
wrist, which is my wrist of prime use.
So…..I’ve had a new pair of stock (you old timers here know I’m a 95% purist), repeat,
stock rear leaf springs for her but haven’t had the strength or pain endurance to install
them up till now.
I’ve not had the privilege of changing the rear springs on a 3604 with the rear fenders
and running board aprons still installed on the truck. According to the service manual,
it’s a simple matter of installing J-1436-9 adaptor to the J-1436 bushing installer and
popping the spring pin out after the lock bolt is removed.
That’s all fine and dandy….if the fenders and apron are off!!! But with them on there is
no way to use a slide hammer, just simply isn’t any room, period.
So (again)…….either I spend the day pulling the rear fenders and aprons or come up with
some sort of fixture that I can pry the pins out with crow bar or some similar sort of leverage.
Or…..maybe, just maybe there’s still an old Chevy mechanic still kickin’ out there who has
a secret way of pullin’ the pins without dismantling the customers truck.
Denny Graham
Pullin’ his pin (i.e., spring pin) in Sandwich, IL

Hello, Denny

Hope you are healing well. It is good to "hear" from you.

As usual, I might be misunderstanding the bushing you are referring to, but, here is a thread with a spring perch bushing remover. I revised the design for use with a beefier remover-bolt.

If I am way of base, just let me know.

Nope, not the bushings Tim, got new springs for my 3/4 ton from Eaton Detroit Spring.
Mike makes them off the original blueprints he says, they've already got the brass
bushings pressed into them.
The stage that I'm at is just getting ready to pull the "spring pins" to remove the old
springs. They might just slip out but I doubt it. So I'm anticipating the worst case.
I always approach it that way then when the worst case happens.... I'm not disappointed.
If those pins just slipped out.....well that would be great, like a bonus, but I know better.
I'll bet I'm in for a wrestling match.
Here's what I'm talking about, it looks like there is more room between the fender
and the rear shackle, but it's really only about 8 or 10 inches and again, not enough
room to get a slide hammer in. And the front is only 4 or 5 inches away from the apron.
http://www.pbase.com/dennygraham/image/166162303
http://www.pbase.com/dennygraham/image/166162304
So....I'll try to see if I can work them out but its looking more like I'll be pulling the fenders
and running board aprons off so I can use a slide hammer.

Hows the life as a country gentleman going??? You and the little woman getting used to
the life of leisure??
What cha working on now that you have all the time in the world?

Moderator: It's my thread so I can talk off topic if I want to!!!!!
Denny G
Sandwich, IL

Denny, I'm doing the same thing swapping out the springs. I was doing well using a 1/8" pipe and a end cap with a 1/2' fender washer banging on that washer with a hammer. Pipe is screwed into the grease fitting hole.

What I wasn't aware of is that the SPACERS go on the outside of the spring.

Now the shop manual says the spacers go on the inside of the spring yet I've measured and determined that the spring spacers need to, and are easier to install on the outside of the springs.

Sense your springs are still installed note where the spacers are, We're approaching a correction to the shop manual. So far two of us (3600) have found out that the spacers are located on the outside of the spring hangers.

I did remove the Fender after installing one spring incorrectly gracious it was a lot easier. Tie a two by four to your engine lift and tie your fender to that being careful removal is successful. I did that on the opposite side of my truck.

Spacer washer is to the outside of the spring. The Forgings are the same for
the ¾ thru 2-ton trucks but the springs are different width, that’s the reason
for the spacer. 1 1/2 & 2-ton had 2 1/2" wide springs.
This truck was all original when I bought it. Talked to the original owners
about what had been done to it over the years and the springs are the
ones it came with.
http://www.pbase.com/dennygraham/image/166164955
No problem holding up the back end.
http://www.pbase.com/dennygraham/image/166164954
But.....getting the U-bolt nuts off was a bear and that took me most
of the afternoon. Had to unscrew them 1/6 of a turn at a time with a
extra-long breaker bar. Even the ¾’ drive earthquake impact wouldn’t
budge them with 1200 ft. lb. of torque. Thought that would have twisted
the bolts off it the nuts got stuck.
Now that the rear pin is out, just have to figure out how to get the front
one.
Almost positive I’m gonna have to pull the running board aprons.
So…..that’s one dang near out. Looks like I’ll be spending the rest of
the weekend on this project.
dg

Denny,
On my 50 1 ton I took out the pins from the top of the shackle. On my frame there is a hole on the backside of the pin which allowed me to simply drift the pin out by "pushing" it rather than pulling. I was then able to do the lower pins on my workbench. I was expecting a bear of a fight too, but it went extremely smoothly. Mind you, I zip cut my old u bolts out, had new ones built and dropped my rear end to pull both spring sets for an overhaul.
Check up inside of your frame for these holes on the top pin. maybe you'll get lucky like I did if you're going as deep as I did.

As Fox said, there is a hole in the frame that you can put a long drift through and tap the pins out from the backside. At least my '50 3600 had the holes there... and my spacers were also on the outside when I took the rear springs off. A bench grinder is my tool of choice for removing U-bolts. Yours sound like toast anyway, if you had that much trouble getting the nuts off.

Thanks for the tip Fox, and you to Dave. I just rolled under to check that out
while the coffee’s a brewin’. Yep…..got em holes thru the inside of the frame
at the back and thru the gusset at the front. Man that would really be a big help
if they line up as you say, and they do look like they line up. Never would have
thought to look thru the inside since the service manual never mentioned it and
working on my back half in the dark with the bed and fenders on doesn’t show
much from the bottom side. If that pans out you’ve just saved me a days’ worth
of work, and that orta be a in the Tips & Tricks.

And I did have Eaton send out new U-bolts with the springs in anticipation of
a problem just like I’m having. Also needed shorter U-bolts because I’m removing
the auxiliary stack that they had on top. Not a fan of re-using old bolts that have been
under a frame and subject to the weather, rocks and tree stumps for 70 yeas.
I’d burn them off but I’m not nuts about that with all the crap I’ve got in the barn
that could catch fire. Most of my burning I keep on the other side of the barn
where I do my welding. Besides, I’m not a very good hacker and I’m not working
on a flat rate so although I’ll never use them on a vehicle, I might find a use for
them somewhere else around the shop. And what the heck…..I needed the
exercise anyway, right?
Thanks for the tips guys, I knew I could count on someone having gone thru
this punishment before to find a simpler way of approaching it.

Denny Graham
Sandwich, IL

A few weeks ago I replied to a question about the spacers by pointing to the instruction in the shop manual. The other day I checked my 1 Ton and the spacers are on the outside. I am quite sure that when rebuilt my truck I put it together the way it was when I got it.

It is common to plan on replacing U-bolts whenever they are removed, especially if one lives in the 'rust belt.'

Ed

Since this seems to be one of those "How did they do it at the factory? areas of question, I'll make
a point of taking some measurements.The location of the spacers can shift the center line of the
spring about an inch, so it should be pretty obvious where they belong once the center line of the holes in
spring perches are determined. That should settle it one way or the other whether the
service manual is right or wrong. Remember now....those manuals were written from
the engineers notes by a technical writer who probably never even saw the under
side of one of these trucks.
The tip than Fox and Dave posted was a good one and made the job of removing the pins
a snap. I'll have to replace a couple of the pins because of wear and I need to order
bushings for the shackles, Other than that, its just a pain in the ars crawling around
under these old trucks at my advanced age and damned hard to even get up off the
floor with the remnants of this broken wrist.
If anyone is contemplating a spring replacement, I'd highly recommend Eaton Detroit Spring.
My new springs are a near perfect match for the original springs. Only one small item the
is different, the rebound clips on the old spring were 1/4 x 1 with 3/8 bolts and the replacements,
3/16 x 3/4 with 5/16 bolts.
http://www.pbase.com/dennygraham/image/166170931
DG

Well…..you guys ready for this????
I dropped a plum bob from the spring perch center on the axle, and
double checked it with a ’47 ¾-ton axle that I’ve got out back of the
barn; 42.5” Center Line on both.
Then laid out the 36” frame width plus the 4.25” for each side of the
spring hanger to their outer edge, minus 2” to the center line of the two
springs and come up with……42.5”.
Which means there is a .5” gap at the “inside” of each of the spring hanger.
So……your .5” shim washer belongs on the “inside”, just as the service
manual says.
This tells me that somewhere down the line the springs had to have been
removed on my truck…unless they were improperly placed during production.

Denny Graham
Sandwich, IL

Well Don't understand but. WIth my New Detroit Eaton springs installed with the spacer on the outside.
Measuring Center Line to Centerline of the tits that go into the diff is 41 5/8. Measured the landings on the differential housing C/L to
C/l and got 41 5/8. All measurements +-1/8"

So I'm working on a '52 and Denny is working on a '47. Wonder when the change happened. That put the pacers on the outside. The tip. About the holes on the inside of the frame is well worthy of a ... special report.

Shouldn't make any difference Julian, '47 to at least '55 1st. 3604. Also Chevy
and GMC should be the same.
Mine Old Blue happens to be a '50 by the way which is 42.5", as is the '47 GMC
that is in the picture below.
The spring center line can only be two widths using the stock .5" spacer washers.
its either 42.5" or 41.5". That is arrived at by taking the frame width, 36" plus the
distance from the frame to the inside of the hanger opening, 1.75" (twice) then adding
1" to each side for the leaf center line, if you were to putting the springs in with the
spacers on the outside and that wold give you 41.5", Shift the spacers to the inside
and you have a spring center line of 42.5" which matches the spring pads on the
HO52 axle housing..
Now....the most accurat way to measure the center line of the 2" pads welded to the
housing, is to drop a plum line from the (inside or outside) edge of the pads making
a mark on the floor and then adding or subtracting 1" to that for the center line. That
will be 42.5".
http://www.pbase.com/dennygraham/image/166182159
Denny Graham
Sandwich, IL