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#1 |
Registered User
Join Date: Jun 2005
Location: sc
Posts: 77
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1 more shackle install question
Does any one think that When I install my lowering shackles (2") that I will need to correct my pinion angle with wedge shims? I am only lowering the rear 2". The front is going to stay at factory height, so the truck will be sitting level. Or will it not be enough to hurt anything?
Thank you Jeremy
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86 c-10 383 w/ sportsman II heads comp 286h cam Edlbrock RPM Performer intake Holley 750 th350 w/2400 stall 3.73 gears with powertrax No-Slip posi unit. Just broken in good. Will get a 1/4 time this week. |
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#2 |
Registered User
Join Date: Apr 2005
Location: Tulsa Oklahoma
Posts: 943
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i would like to know also i am doing the same thing
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square body trucks an addiction or an investment either way they consume all my extra time and money |
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#3 |
Registered User
Join Date: Jun 2005
Location: sc
Posts: 77
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also I noticed in summitt that the shackles PN sum-g904000 say they are for 1988-2000 models. Will these work on an '86?
Jeremy OOPS never mind just noticed the sum-g756 which is for my application. SORRY.
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86 c-10 383 w/ sportsman II heads comp 286h cam Edlbrock RPM Performer intake Holley 750 th350 w/2400 stall 3.73 gears with powertrax No-Slip posi unit. Just broken in good. Will get a 1/4 time this week. Last edited by red86chevy; 08-17-2005 at 08:20 PM. |
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#4 |
yeller
Join Date: Oct 2001
Location: Twin Cities
Posts: 13,826
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your pinion angle will be just fine.
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Jeff 73-87.com 73-87.com Facebook page 73-87 cab corner 6x9 speaker brackets for sale 67-72 cab corner speaker brackets for sale 47-54 cab corner speaker brackets for sale |
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#5 |
Registered User
Join Date: Jun 2005
Location: sc
Posts: 77
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Thank you.
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86 c-10 383 w/ sportsman II heads comp 286h cam Edlbrock RPM Performer intake Holley 750 th350 w/2400 stall 3.73 gears with powertrax No-Slip posi unit. Just broken in good. Will get a 1/4 time this week. |
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#6 |
Parts and more parts
Join Date: Nov 2003
Location: Lebo, Kansas (middle of nowhere
Posts: 6,821
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I have lowered more than one truck, the amount that you are going is not going to be an issue. You can even put the front hangers on for the full four inch drop and it will be just fine. The major companies that sell these items have worked out all of the particulars and if it needed pinion work then they would offer that info when you purchased the kit. Belltech, DJM, and others are silent in thie area for what you want to do.
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#7 |
Registered User
Join Date: Sep 2004
Location: Elkins, West Virginia
Posts: 2,542
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mines lowered total of 7" in rear...no shims...pinions fine
![]() imo, the "higher quality" lowering components have this worked out in there stuff, so shims arent necessary....imo
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1987 350 TBI lowered 5/7 |
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#8 | |
Account Suspended
Join Date: Oct 2002
Location: Elkhart, IN
Posts: 6,400
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Quote:
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#9 | |
Registered User
Join Date: Sep 2004
Location: Elkins, West Virginia
Posts: 2,542
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Quote:
well, i was actually talking more about the design of the flip kit and the angle to which its made to go on the rear....(i should have been more specific)
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1987 350 TBI lowered 5/7 Last edited by bigarmzz; 08-18-2005 at 07:19 AM. |
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#10 |
Account Suspended
Join Date: Oct 2002
Location: Elkhart, IN
Posts: 6,400
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this thread is about shackles, not flip kits.
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#11 | |
Happy to be here
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Location: Cypress, TX
Posts: 39,023
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Quote:
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#12 |
Until Seventy Times Seven
Join Date: Feb 2005
Location: Rocky Mountain Front Range
Posts: 1,301
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Won't dropping the rear 2" with just shackles change the pinion angle enough to warrant shims? I figure 4" shackles will drop the rear 2", but also rotate the pinion about 4* downward. I figure by dropping the rear a couple of inches may also (just slightly) affect the angle of the tailshaft relative to the original pinion/tailshaft position. I'd think a 4* shim would correct the pinion angle. Maybe, someone who has done this can check the angle of the pinion and tailshaft.
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boxRODz 1983 C10 SWB Fleetside When two halves is gone, there's nuthin left. Two nothings is nuthin. That's mathematics son. You can argue with me but you can't argue with figures. Two half nothings is a whole nuthin... |
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#13 |
Happy to be here
![]() Join Date: Mar 2000
Location: Cypress, TX
Posts: 39,023
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It's not just the amount of drop that determines if you need a shim. The amount of driveline angle that was already there is significant too. It seems that these trucks have enough angle that a shackle has little or no effect on them.
As an example of what I am refferring to, my 02 Harley F-150 had to have a shim with a 2" shackle because the driveline angle was almost flat to start with. If I had pics it might help clarify this... ![]() |
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#14 | |
Until Seventy Times Seven
Join Date: Feb 2005
Location: Rocky Mountain Front Range
Posts: 1,301
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I follow you regarding the driveline angle of these trucks. These trucks in stock form do have a significant amount of driveline angle.
But, I guess I was more concerned with the angle of the pinion in relation to the angle of the tailshaft. Whenever altering the rear suspension, I though the angle of the pinion in relation to the angle of the tailshaft had to be preserved, i.e. the angle of the pinion equal (or nearly equal) but opposite to the angle of the tailshaft. Using a shackle to raise just the rear portion of the leaf spring to obtain a 2" drop rotates the angle of the pinion downward. For a 52" spring pack, I figure by just over 4*. To preserve the angles, the pinion has to be rotated upward 4* to match that of the tailshaft. I believe the margin of error is around +- 1*. ![]() Quote:
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boxRODz 1983 C10 SWB Fleetside When two halves is gone, there's nuthin left. Two nothings is nuthin. That's mathematics son. You can argue with me but you can't argue with figures. Two half nothings is a whole nuthin... |
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#15 | |
Registered User
Join Date: Sep 2004
Location: Elkins, West Virginia
Posts: 2,542
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Quote:
wtf?...uh...yes it does...duh.. ![]() this thread is about gaining information about pinion angles as it would be directly related to lowering components in general...its hard to speak of just shackles when a question arises concerning a lowered vehicle ![]()
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1987 350 TBI lowered 5/7 Last edited by bigarmzz; 08-19-2005 at 11:49 AM. |
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#16 |
Parts and more parts
Join Date: Nov 2003
Location: Lebo, Kansas (middle of nowhere
Posts: 6,821
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On our old Junky Chevys and not a ford, we have no problem with changing out the rear shackles. The only thing that you will have to do is cut the bed support bar so that the shackle will clear it. As I stated earlier, the Major designers sell these on a regular basis and do not include the shims. However, shims are easy to buy and install if that becomes the issue. I used to have to do that kind of work at the place I used to work. I presently have three trucks that I own that are lowered and there are no shackles in any of them. Also there are no vibrations, even at speeds greater than 80 MPH. I did the shackle only drop first and then went to the 4" drop with the front hangers, the systems are pretty self forgiving. I also have dropped a couple later model trucks 1991 and later with no ill problems on them. Go forth put the shackles on and try it.
Last edited by piecesparts; 08-19-2005 at 12:14 PM. |
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#17 |
Registered User
Join Date: Oct 2002
Location: Ontario, canada
Posts: 138
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Just something else to throw into the discussion.
I believe that the 2-piece drive shafts are more prone to vibration problems when lowering the rear suspension than the 1-piece drive shafts are. With a two piece you can modify (raise) the hanger bearing to correct the angle. |
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#18 |
Parts and more parts
Join Date: Nov 2003
Location: Lebo, Kansas (middle of nowhere
Posts: 6,821
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Actually some kits send out a spacer setup for raising the rear of the tranny t align the shaft with the reaend in the other respect. It boils down to what ever you do to the rear end, you should analyse the driveline and it's geometry. This is not rocket science, or there would be a bunch of us country boys sittin' at the gas pump wonderin how it is done. GO FOR IT....
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#19 |
Until Seventy Times Seven
Join Date: Feb 2005
Location: Rocky Mountain Front Range
Posts: 1,301
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Thanks for the posts, piecesparts.
I'm just trying to cover the bases. You're right, there is rhyme and reason to this.
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boxRODz 1983 C10 SWB Fleetside When two halves is gone, there's nuthin left. Two nothings is nuthin. That's mathematics son. You can argue with me but you can't argue with figures. Two half nothings is a whole nuthin... |
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