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56 Dodge D500 Springs and Front Sway Bar Part Numbers Jump to page : 1 Now viewing page 1 [50 messages per page] | View previous thread :: View next thread |
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56D500boy |
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Expert 5K+ Posts: 9900 Location: Lower Mainland BC | . Let me first say, I in no way set out to contradict any previous discussions, especially any made by those no longer able to discuss the topic (think d500Neil (Neil Vedder)). That said, I might have bumped into information that does just that. (Sorry Neil, RIP) *********************** Before I get started, it might be good to show the generic front and rear spring definition diagrams (primarily to show the sections where the PN listings are located) see Front and Rear Spring Diagrams below So, jumping in, when the 56 D500s were first announced to the public on Dec. 22, 1955, the information was somewhat incomplete. But there were, for example, front spring and rear spring PNs for this new D500. The front D500 springs were given a PN of 1630 161 and the rear springs PN 1675 690. The 1630 161 front springs were unique to the D500 but the 1675 690 six-leaf rear springs were shared with the P29 Plymouth Fury. See 1630 161 and 1675 690 PN listings below The photo below (courtesy of Dave H.) shows the normal 5 leaf 56 Dodge rear spring (5 leafs) and the 56 Dodge D500 rear spring (6 leafs) See spring photo below I am not sure what happened between December 22, 1955 and January 12, 1956 but by January 12th, there was a new Bulletin issued with some new part numbers for the springs, presumably more heavy-duty to meet racing needs. See the Jan 12, 1955 Bulletin below The new listing for optional (racing) front springs was PN 1618 084 which was listed as both the Left, Heavy Duty, C67 AFTER W55-40073, C71, except Estate Wagon and the Right, Heavy Duty, C68, C72, except Estate Wagon. I think the take away, is Heavy Duty springs from the Senior Chryslers (BUT not Imperials). The new listing for the optional (racing) rear springs was PN 1635 594 which is listed as the Heavy Duty, non-Suburban (wagon) rear 55-56 Dodge and Plymouth Taxi spring. I don't have photos of this spring but I assume that it would have more leafs than the normal D500 spring. You might note that in the earlier D500 Rear Spring thread there was conjecture that the heavy duty rear racing spring would have come from the 120 in wheel base Dodge station wagons. Turns out that this is wrong since the heavy duty suburban rear springs were listed as 1635 602, not the 1635 594 that was called out in the Jan. 12th Bulletin. See 1618 084 and 1635 594 PN listings below Finally there was the front anti-sway bar, i.e. sway eliminator (bar). There was no PN given in the Dec. 22, 1955 announcement but there was a PN given in the January 12th Bulletin. That PN was 1639 165 which crossed all the 56 Desotos and Chryslers, i.e. heavy duty for a lowly Dodge. See Sway Eliminator Diagram and 1639 165 PN listing below One Previous 56 D500 Rear Spring Thread: http://www.forwardlook.net/forums/forums/thread-view.asp?tid=33272&... Edited by 56D500boy 2020-01-17 1:43 AM (55-56FrontSuspensionDiagramFlaggingTheSteeringKnuckleSupport.jpg) (55-56GenericRearSpringDiagram.jpg) (CleanImageOfTheDec22_1955_J10D500Bulletin.jpg) (56D500Parts_FrontSprings1630161.jpg) (56D500Parts_RearSprings1675690SharedWith56Fury.jpg) (ComparisonOf5LeafAnd6LeafSprings.jpg) (Jan12_1956_SupplementToB_BulletinJ10.jpg) (56D500Parts_FrontSprings1618084.jpg) (56D500Parts_RearSprings1635594HeavyDutySharedWith56PlymouthAndDodgeTaxis.jpg) (Generic55-56FrontSwayEliminatorDiagram.jpg) (56D500Parts_FrontSwayBar_16939165_CrossTo56DesotosAndChryslers.jpg) Attachments ---------------- 55-56FrontSuspensionDiagramFlaggingTheSteeringKnuckleSupport.jpg (123KB - 251 downloads) 55-56GenericRearSpringDiagram.jpg (91KB - 267 downloads) CleanImageOfTheDec22_1955_J10D500Bulletin.jpg (211KB - 265 downloads) 56D500Parts_FrontSprings1630161.jpg (184KB - 248 downloads) 56D500Parts_RearSprings1675690SharedWith56Fury.jpg (177KB - 255 downloads) ComparisonOf5LeafAnd6LeafSprings.jpg (169KB - 285 downloads) Jan12_1956_SupplementToB_BulletinJ10.jpg (203KB - 265 downloads) 56D500Parts_FrontSprings1618084.jpg (169KB - 254 downloads) 56D500Parts_RearSprings1635594HeavyDutySharedWith56PlymouthAndDodgeTaxis.jpg (152KB - 259 downloads) Generic55-56FrontSwayEliminatorDiagram.jpg (50KB - 262 downloads) 56D500Parts_FrontSwayBar_16939165_CrossTo56DesotosAndChryslers.jpg (205KB - 282 downloads) | ||
56D500boy |
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Expert 5K+ Posts: 9900 Location: Lower Mainland BC | . Forgot that I had these photos of a July 56 build 56 D500 that only had the five leaf springs that I took and photos of a D500-1 "Race Car" chassis springs that I was given by Gary R. (Thanks Gary). These ones have 7 leafs on the right side and 8 leafs on the left side (Yikes!!). Not sure if these are the taxi springs or not (nothing to compare to). Edited by 56D500boy 2020-01-17 7:58 PM (LangleyBC56DodgeD500Coronet_RightSideViewWithDodgeBadge.jpg) (LangleyBC56DodgeD500Coronet_BodyDataPlate_CloseUp.jpg) (LangleyBC56DodgeD500Coronet_EngineBay_RightSide.jpg) (56D500With5LeafSprings_July56Build.jpg) (D500Dash1RaceCarRightRearSpring_7Leafs.jpg) (D500Dash1RaceCarLeftRearSpring_8Leafs.jpg) Attachments ---------------- LangleyBC56DodgeD500Coronet_RightSideViewWithDodgeBadge.jpg (133KB - 271 downloads) LangleyBC56DodgeD500Coronet_BodyDataPlate_CloseUp.jpg (198KB - 261 downloads) LangleyBC56DodgeD500Coronet_EngineBay_RightSide.jpg (170KB - 272 downloads) 56D500With5LeafSprings_July56Build.jpg (136KB - 260 downloads) D500Dash1RaceCarRightRearSpring_7Leafs.jpg (167KB - 263 downloads) D500Dash1RaceCarLeftRearSpring_8Leafs.jpg (213KB - 258 downloads) | ||
56D500boy |
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Expert 5K+ Posts: 9900 Location: Lower Mainland BC | . Hunter D. (aka "Cooter") was nice enough to recently send me photos of the rear springs on his mid-December 1955 built 56 D500 Custom Royal Lancer which has D500 engine number D500-1003 (the third production 56 D500 engine) (confirmed by his car's IBM card). As you will see in the photos below, the original 56 D500 rear springs had 6 leaves both left and right. Hunter's car also has the 56 Chrysler-based 7/8" front sway bar and between the rear springs and the front sway bar, etc. he says that the car corners amazingly. Thanks Hunter! Edited by 56D500boy 2022-11-19 2:46 AM (Hunters56D500RearSprings_left.jpg) (Hunters56D500RearSprings_right.jpg) Attachments ---------------- Hunters56D500RearSprings_left.jpg (150KB - 77 downloads) Hunters56D500RearSprings_right.jpg (169KB - 75 downloads) | ||
PolyJ |
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Veteran Posts: 143 Location: Denver, Colorado, USA | Hey Dave, (1956_Dodge_SRI.jpg) Attachments ---------------- 1956_Dodge_SRI.jpg (169KB - 85 downloads) | ||
56D500boy |
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Expert 5K+ Posts: 9900 Location: Lower Mainland BC | . I am currently investigating what will be the best way (for me) to install a 1639 165 56Chrysler 7/8" front sway bar on my 56 Dodge D500 "Lite" (Special). I was doing so because I believed that the early factory D500s got the thicker bar. So I contacted Hunter D. (the owner of the 56 D500 Custom Royal with engine D500-1003) to a) check his car's front bar diameter and b) how it was mounted (assuming that it was the 7/8" Chrysler bar). After a few days, Hunter got back to me and showed me photos of him measuring his D500's front bar: 0.8125" (i.e. 13/16"). This was confusing to me because I thought from the early Dodge D500 parts lists (posted above) the front bar was supposed to be the 7/8" 1639 165 bar. Hmm.... Peter S (from Caprock Classics) who has installed a 7/8" bar on his 56 Dodge suggested that I might want to review those early parts documents again. So I did. Conclusion: I am an idiot. Indeed the early 56 Dodge D500s got special stiffer and lower front coil and rear leaf springs. *HOWEVER* there was NO MENTION of any stiffer sway bar in the Dec. 22, 1955 D500 parts list. There was no special sway bar listed at all (My head was about to explode). Then I revisited the January 12, 1956 Supplement to the Dec. 22/55 list (posted above) in which a number of Options were listed as being available for D500s. It was in that list that the thicker 56 Chrysler 7/8" front bar, PN 1639 165, was listed as optional. Along with thicker 7 leaf 1635 594 taxi rear springs. So now I don't know how wise it will be install the stiffer 56 Chrylser front bar on my otherwise very soft 56 Dodge with 5 leaf rear springs. I will do it anyway but I am not sure if it will be a keeper without going to stiffer rear springs to balance the stiffer front suspension. Can anyone say "Danger!! Slippery Slope ahead?" Edited by 56D500boy 2022-11-28 4:57 PM | ||
Powerflite |
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Expert 5K+ Posts: 9654 Location: So. Cal | The real danger comes from having a rear suspension that is too stiff relative to the front suspension because that will result in the rear end breaking away in a hard turn, causing the car to spin. Having the front suspension overly stiff doesn't result in a dangerous situation. It just makes it so you can't fully realize it's capability because you are limited by the lack of rear stiffness. | ||
56D500boy |
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Expert 5K+ Posts: 9900 Location: Lower Mainland BC | PolyJ - 2022-11-23 5:35 PM I wanted to post the SRI screenshot here since it will help narrow down your search for details. Thanks for that Justin. I used that info to contact a local firm that is, in theory, a member of the SRI. I didn't get very far with them But it gave me incentive to find the source of the info that you posted. Took a little work but I found it. Volume 12 of the Leaf Spring Institute's Data Manual: http://springresearch.org/pdf/volume_12.pdf Here are two excerpts from Vol 12. One for the 55-56 Dodges and one for the 55-56 Plymouths. I need to check whether there is a common 6 leaf spring between them that would be the 6 spring D500 and Fury spring. And also compare the SRI Vol. 12 info to the Stengel Bros. website spring info (has more details). Edited by 56D500boy 2022-11-29 5:13 PM (SRI_Vol12_Cover.jpg) (SRI_Vol12_Pg11of57_DodgeRearSpringInfo.jpg) (SRI_Vol12_Pg43of57_PlymouthRearSpringInfo.jpg) Attachments ---------------- SRI_Vol12_Cover.jpg (199KB - 85 downloads) SRI_Vol12_Pg11of57_DodgeRearSpringInfo.jpg (213KB - 88 downloads) SRI_Vol12_Pg43of57_PlymouthRearSpringInfo.jpg (219KB - 81 downloads) | ||
56D500boy |
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Expert 5K+ Posts: 9900 Location: Lower Mainland BC | . And furthermore, the next issue of the SRI info for cars in 1960 (covering 1950 to 1960) didn't change any of the 1956 Dodge info that was previously presented in 1956. http://springresearch.org/pdf/volume_14.pdf Edited by 56D500boy 2022-11-30 2:13 AM (SRI_Vol14_Cover.jpg) (SRI_Vol14_pg11_DodgeRear.jpg) Attachments ---------------- SRI_Vol14_Cover.jpg (182KB - 85 downloads) SRI_Vol14_pg11_DodgeRear.jpg (198KB - 82 downloads) | ||
56D500boy |
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Expert 5K+ Posts: 9900 Location: Lower Mainland BC | . I was looking for something else this AM and re-found the May 56 Hot Rod article about the new D500 written by "Racer Brown". This is available in my personal library and here: http://www.forwardlook.net/forums/forums/thread-view.asp?tid=64334&... The article contains some interesting information. I can NOT attest to the accuracy of what he stated back then but here are a few tidbits: D500 Front Coil Spring rates: D500 = 581 lbs/in D500-1 = 619 lbs/in Rear Springs: D500 = 110 lbs/in D500-1 = nothing mentioned but there is a photo of an "8 leaf" rear spring. Not sure if that was real or a typo. Plus there is a comment that the D500 and D500-1 chassis were both 1.5 inches lower than standard Dodges. | ||
PolyJ |
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Veteran Posts: 143 Location: Denver, Colorado, USA | Interesting new developments, Dave. Pertaining to the Hot Rod article's claimed "8 leafs," that article seems to have some inaccuracies since it also claims the car weighs nearly 3,900 lbs amongst other things, so I assume some of the content is either a typo or outright made up. The article photo of the rear end, while grainy when I magnify it, doesn't show a pack and u-bolts tall enough for (8) 1/4" leafs and looks more like 5 or 6. I'm sure there were a very small amount of factory experimental cars and custom orders by professional race teams that could have seen the car leave the dealership with tuned suspension for circle-track racing like Gary's 7- and 8-leaf combo, but they would be very rare instances. | ||
PolyJ |
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Veteran Posts: 143 Location: Denver, Colorado, USA | While the historical context and discovery process is great and worthwhile, in the end the '56 Dodge rear suspension even with the 6-leaf 1635593 760lbs capacity springs has some serious design flaws. One major issue that I have confirmed exists on every person's '56 Dodge I have spoken to, seen in person, and seen on numerous photos online of cars for sale is the shackle geometry. Either the leaf spring is too long eye to eye or the chassis shackle boss is placed too far forward. All factory springs are 49" long eye-to-eye, which matches the OEM springs I removed. Brand new 6-leaf 760lbs springs are flat and the shackles extended as far back as they will go under the car's weight and no additional load. This position is technically "binding." With the shackle in this position as close to the datum line (drawn through the two eyes), the rear suspension will both be a harder ride--ironic since Dodge was so focused on ride quality--and force the spring to go concave (center up toward the chassis) when any additional load is applied such as passengers, trunk weight, when the car comes down after hitting a dip, when body roll occurs in a corner, or under acceleration when the weight transfers back. Proper shackle geometry for a street car should have the shackle almost 90° to the datum line with the leaf-spring shackle bolt angled back no more than about 10° with the car at rest under its own weight. As passengers/trunk weight and road physics apply more load to the rear body, the shackle already slightly angled back should naturally swing back to absorb more of the load before the leaf springs bind and are are forced concave to absorb the load. When I first noticed the shackle geometry with the OEM springs, I assumed the springs were badly sagged, so I was surprised when the new springs resulted in the same terrible shackle geometry and then when I confirmed this geometry is as-designed since I haven't found a single case where the shackle isn't maxed out or almost maxed out. Along with the incorrect shackle geometry, even the "heavy duty" 6-leaf 760lbs springs are too soft for anyone driving curvy roads or road/circle track courses. The brand new 760lb 1635593 springs I installed sagged and would cause excessive rear body roll when cornering. Correct shackle geometry would help stop some of the sagging but not all. While I haven't installed them yet, to correct both the shackle geometry and the spring capacity issues I had ESPO build me a new set of springs that have the 8-3/8" arch of the convertible 1636860, measure 47-1/2" eye to eye (1-1/2" shorter than factory), and have a 7-leaf pack like the suburban 1635602. With the additional arch and seventh leaf, ESPO says the spring is around 860lbs capacity. The 1-1/2" shorter spring will place the shackles closer to 90° to assist with ride quality and stop the springs from having to concave under most driving conditions. As I tune the suspension at the track and on the street, I can remove leafs as necessary if the suspension is too stiff, which I doubt will be the case. We'll see how this all pans out. | ||
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