Rack & pinion for my P15

[Oldguy48]

Planning a rack & pinion conversion for my P15 this winter. I’ve been researching the forums & the internet for pointers/tips/etc. before I tackle this. I’ve also gleaned some good information from Rustyhope. I rescued a rack & pinion unit from a Chevy Beretta/Cavalier to use for fit-up measurements, and eventually a core when I purchase a remanufactured one.

Has anyone here made this conversion, and if you did, how do you like it? I find it almost a necessity since I installed the radial tires (and I‘m not going back to bias ply). At very low speeds, I struggle to maneuver the car (I‘m not getting any younger…just older and weaker). Once I’m rolling, all is OK.

If anyone has any input regarding this modification, I would appreciate viewing it. Thank you.

Wayne

Edited December 6, 2013 by Oldguy48

[chopt50wgn]

 This conversion from Fatman was on my 50 Ply wagon when I bought the car. The guy and his son did the setup. The only thing I did not like was the R&P was directly under the motor in the middle of the front crossmember. Now I do not know if this was done correctly and that was how the steering was meant to be. I put a 360 mopar in my wagon and there was no way the pan would fit. I changed over to a complete Fatman stub with R&P,PS,and coilovers with discs. Was lots more work and money but ride is much better and motor fits better as well.

[blucarsdn]

I have known several guys that tried to make a "silk purse out of a pigs ear" by attempting to convert the stock front end of older cars to disk brakes and rack-pinion steering... This conversion usually results in an accident looking for a place to happen..

Back in the so called "Good Ol Days" prior to the emergence of the after market performance parts industry, the major sourse of parts to improve the handling of older cars, the local junk yard, was our only sourse of parts..

The Mustang II's, Gremins, Camaro's, etc., gave up their front clips for grafting onto the front ends of every make and model of older car/truck on the road.. All of us have seen some pretty wild unsafe adaptations under cars..

Fast forwarding to here and now, it is generaly a waste of time and money to try an adapt a front clip and/or the parts there-on to a older car when you can purchase a completely new setup, that is engineered to fit the car that you are working on...

I, we, put a Fatman Stage II ftont clip under my '39 Plym conv. cpe.. It has power rack-pinion, 12" power dick brakes and 15x7 steel wheels with P205-65/15R tires. The car handles like a new car, stops on dime in a straight line.. In the heavy traffic that we have to deal with today, I feel very safe in the car, especially on the highway cruising at 70 plus...

[Plymouthy Adams]

blucarsdn

Senior Member, have way too much spare time on my hands

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Posted Today, 01:03 PM

I have known several guys that tried to make a "silk purse out of a pigs ear" by attempting to convert the stock front end of older cars to disk brakes and rack-pinion steering... This conversion usually results in an accident looking for a place to happen..

 

 

there is nothing wrong with a properly installed front clip....and nothing wrong with retrofitting old to new...the very Fatman kit you described  and applaud is every bit the exact process you are condemning...and for the Fatman to work on a stock 39 and up Mopar car chassis...will require you to cut and stub in front frame rails..if this is not a form of clipping then it is very evident that this procedure was farmed out and you have no first hand experience with this..oh and even without shipping and labor cost involved...a modern clip of Mopar design can usually be had for under 300.00 complete with brakes where as just the front frame rails for the Fatman are 600.00 uninstalled and no freight yet paid...not to mention the MUSTANG II copied Fatman IFS is going to run about 2000.00 of course you can go higher priced or lower price depending on completeness and parts finish...or buy a kit that again is quite a bit more expensive over a clip..this kit must be properly installed and welded by either yourself or farmed out again at a higher labor rate compare to a engineered front clip where in the end the geometry will not come into question..

 

I am not condemning your response or your choices..I am only saying that both routes involved similar processes...it is what you want, what you can do yourself, what you wish to spend...but never one better than the other....the modern suspension are in my humble opinion better engineered than aftermarket IFS stubs and kits/components..and..as for safety....modern clips have built in crumple zones for absorbing energy on impact without transferring to the passenger compartment like in the older cars and straight frame rails and IFS attached..

 

So in reality there are many side to the equation and lots to consider on the build....many options out there...

Edited December 7, 2013 by Plymouthy Adams

[DJ194950]

Tim,

Fatman stub frames are now over $1000 plus shipping.

Price of steel, labor went way up??

Still, ease of install vs. cut off pieces of frames of other cars/trucks does help. Rad. mounts, bumper brackets-stock fit, etc. on Fatmans are easier if more expensive for sure!

 

How fat is your wallet and talent to do alterations?

 

To each their own.

 

As long as done cleanly And Safely! Do what you can do and complete.

 

Merry Christmas to all.

 

Stay Warm.

 

Doug

[wayfarer]

I'm with Plymouthy Adams. I have seen many well done clips including the 1st Gen Dakota on both cars and trucks. Personally, I am a big fan of the Jaguar IFS as well as the IRS.

The terms 'Fatman' and  'reasonably priced' are mutually exclusive.

[Andydodge]

I must have done something wrong back in the ol' days then as my 1940 Dodge has had a rack & pinion since 1973, 4 wheel discs since 1975/6...all this on the original style front end, ie, 1941-56 Moog cast steel upper arms, stock 1940 Dodge lower arms, and spindle, 1941-56 stub axles, 1" adjustable sway bar, Oz Leyland 11" vented disc brakes, Leyland dual circuit master cylinder & booster, 9" narrowed Austin 1800 Rack & Pinion, modified Valiant upper steering column...........see attached pics.......I have an Oz RHD version of the Cavalier centre steer rack that I am considering installing however what you see is what is there at present & it works fine........andyd

[Plymouthy Adams]

Tim,

Fatman stub frames are now over $1000 plus shipping.

Price of steel, labor went way up??

Still, ease of install vs. cut off pieces of frames of other cars/trucks does help. Rad. mounts, bumper brackets-stock fit, etc. on Fatmans are easier if more expensive for sure!

 

How fat is your wallet and talent to do alterations?

 

To each their own.

 

As long as done cleanly And Safely! Do what you can do and complete.

 

Merry Christmas to all.

 

Stay Warm.

 

Doug

Doug...have you personally done a sub frame and or the fatman frame stubs and eventual install of the MSII IFS?  regardless of which one you do...you have the front bumper to contend with..unless like lots of folks you do a front roll pan and thus do the ole ostrich head in the sand trick.  I cannot after doing three Dakota clips see how it could ever be easier...the Fatman I will assure you will be every bit as involved...and remember you have not even addressed the steering in this Fatman  IFS setup..

 

And for the Dakota subframe..depends again on the year car you stubbing out...49 and up..the early Dakota will insert some 20 inches into the  Plymouth frame..super strong....the 39 - 48 frame however is tapered...a slight mod needs be done to make a receiver for the Dakota to fit..this is super simple.  It is nothing like the GM stubs that are done at the very firewall and do not incorporate any overlap/insert of the two frames..

 

I am not surprised of the price increase in pieces parts though..I looked long ago to the Fatman and ruled it out for way to much cost involved...and was not impressed with the stubs they provide.  There are those that have also cut and boxed the original frame rails but man is this totally involved also.  For the money and time...subframing as I did it (not saying there are other ways nor saying you should do it the way I did)  but considering the last early Dakota entire frame less rear axle was bought and loaded at the wrecking yard and included both front wheels, hubs, brakes, R&P and sway bar for 150.00...this is math my way...

 

My latest subframe was done a bit different as I used a much later model Dakota donor...buying a low mileage V6 with 5 speed and using all components and then selling some bumper parts and body panels not used, the rest to scrap metal I have <500.00 in total for front clip, 210 HP V6 3.7 engine, 5 speed tranny, bucket seats, console, firewall/floor transfer, factory AC, ABS brakes and 3.55 rear ratio all electronics and fuel system carried forward to the Plymouth...I cannot in any logic justify a Fatman over this type set up.....plus the very install of the front subframe is simply a cross X dimensional check..the frame centerline of the stock 48 chassis continues its identical line onto that of the 2004 Dakota frame whereas only the forward mounts had to be transferred to the Dakota part of the chassis...and remember the center line measurement,..this makes mount alignment so simple anyone can do it.lay it on the line and make the install...some may not want to go this extreme with electronics and such...it is not a mandate..only an option open to the builder...

 

Now I am not saying this is not without a lot of measurements and a bit of cutting and welding but again, you going to be doing as much with the Fatman install...probably a bit more involved on the stubs as they are not tied front and rear as the Datkota is when transferred making leveling and paralleling much much easier with the subframe... 

[DJ194950]

Tim,

 

Many points brought up. I do not know if i can respond to all in one post, but yes in my 50 Suburban I did install with Fatman's stub.

Power R&P (my choice over manuel) both BOLT on. Your choice. Front A arms? Use stock or all the way up to $$ polished stainless. Many choices, maybe too many! Again your wallet.

 

Steering, require some U-joints to hook up. How does your stubs steering hook up?  A u-joint, rag-joints?

 

Rad. mounts built into sub.frame to mount rad. in stock position on the Fatman stub plus the stock bumper mount hole are predrilled in the stub. Bumpers fit stock location. I made a choice to fab a replacement gravel pan and fiberglass front bumper to make a look simular to 49 Ply. bumper as 49 bumpers where going for $350+ at the time (7-8 years ago) I changed front sheet metal  and grille to 49 parts, I like the look more.

 

As for the install, just using the stock front suspension before removing it, mark the center lines on the spindles on the floor plus rad. mount centeron on the holes on the floor and match the holes with the holes for same with the Fatman stub which slides Into the stock frame on three sides tightly after cutting off some of the stock frame. Measurements given in the instructions. The fourth side is split at the bend edges and folded inward. Drilling plug weld holes on all four sides and after checking all measurements and center lines, tack welded. Fatman also supplys several fish plates to make sure it is strong as stock or more. Where marks match, weld up. No need for any boxing, frames aleady 4 sided, Fatman stub is not, but with the center crossmember to strenghten I saw and see no need. Running 500+ HP? Maybe then.

 

I have no problems with other stubs used when properly, safely installed as does the Fatman stub require, particularly if one with the correct track width and especially if it can be bought cheaply.

 

I have never done a take off stub replacement job, but have have seen many ugly, poorly done by others! Includes my best friends son (now his) 57 Chev. truck with a Camaro Stub. Front sheet metal barely mounted as are the front bumper. Done before his kid bought the truck.

Said to drive well by the kid, but plan to do a cafefull check with my friend who plans to finish the truck to sell. Needs to be at least safely done.

 

If a stub from a donor and reasonably priced as Tim found ,that fits and you have Tim's drive, experience to go on your own I have no problems and tottaly endorse and support you!

 

Go to it!

 

Best to ya all,

 

Doug

[fstfish66]

my 40 coupe has a fat man  cavilere rack power, that wa in the car when  i   bought it,,if installed  properly,,,,and cant picture being  so far out of wack you cant get a 360 in it,,,  u need  a  dodge truck or van  oil pan  rear sump,,i have a  early  hemi in the car with  a rear sump oil pan,and after market  disc  brakes,, only thing it needs is  new front coils and  dropped up rights,,,, there is no need for a front clip if your original  frame and  componets are in good shape,,,the car could benifit from a bigger front sway bar,,, 

 

if  you do some reading you will see the  40s mopar  front suspension,,other then the front shock  mounts were ahead of there time,,others still using  straight axels,,,mopars were IFS,,  so  no  need for a stub,, fat man  will tell  u  same thing,,

 

now  if  u have a worn out  car,,,it may  be  a  toss up  to  do a clip or  rebuild the original stuff,,,all depends if your capable of doing all the chopping  and  welding,,,  if  not  im  sure the cost of labor  for installing the clip far out  weighs the  cost of  replacing the original  stuff,,,

[chopt50wgn]

There are many pros and cons to this......but it all boils down to how much money you want to spend and how much of the work can be done by you.

I sold my prostreet for a great price and earmarked the money for the upgrades to my wagon. Putting in an IRS was a deciding factor in putting in a new front end as well.

I have a good friend who has a fab shop here in my town and I contracted him to do all the fab work. I do not fool myself into thinking I could do this type work myself so I had someone who knew what the hell they were doing. I can tell you this..........the car drives like a new caddy and handles and stops on a dime.

 I have found with age comes wisdom and knowing ones limitations is foremost when you are behind the wheel.

[blucarsdn]

I learned a long time ago that two wrongs don't make a right, and if you can't do the job right, when are you going to have time to redo it..

I used a FatMan sub-frame under my '39 Plym because they were the only aftermrket vendor that specificly makes front clips for the early Mopars.. I did two years of research before I ever put a wrench to my Plym.. The Fatman "grafted" into the original frame perfectly, all of the brackets were right where they should be.. The core support and bumper brackets were perfectly aligned..

So just what is the big deal about the Mustang II type of front suspension? As it has been pointed out, the majority of aftermarket front clips are based on the Mustang II design.. It was explaned to me by Brett at FatMan that with the advent of disk brakes on the front end of many vehicles starting in about 1969, the design "geometry" of the front ends was not up to the requirements of the disk brakes.. Many attempts were made to correct the problem. Ford used a Euro design in the Mastang II's which corrected the "dive characteristics" of the earlier front ends.. The after market manufactures quickly figured out that with a few simple modifications tthe Ford strut rods could be eliiminated, being replaced with heavier duty components, which made the aftermarket Mustang II type of front end more heavy duty, allowing it's use under larger heavier cars.

The problem with adding disk brakes and rack-pinion steering onto an early front end, is that the actual geometry is all wrong, ergo "bump-steering" and poor stopping control..

My '39 Plym is built to drive, I told everyone that had anything to do with the car that I wanted "a 75 mph left lane car" not something to putt down the  right lane in.. My car handles very similar to my 2003 Mecedes 430 GLC conv.. When the traffic stops, I stop, safely in a straight line... I was on the freeway yesterday, cruising along at 70, all of a sudden red brake lights all over the place, a bed liner had came out of a pickup, two cars hit it.. My Plym made a perfect, straight-line controlled stop.

I know that my line of thought will not have much effect on the thinking of those that are more cost driven, and/or insist on doing things the old way, however, it might encourage someone to think twice before they strart to hack away on their car...

I like the terminology that a very knowledgeble man wrote on another car forum I contribute to... "The most dangerous man in the world is a farmer with a cutting torch and a welder".. 

[wayfarer]

I am unable to use the 'quote' or cut and paste on this forum so I'll simply say that your comment about folks being "cost driven" sounds more like you think we are some kind of cheap bastards for wanting to have both a proper package and not wanting to mortgage the house to fund Fatmans retirement.

And "doing things the old way" is somehow bad? Just because Fatman, or any other vendor, has a flashy product does it automatically make it 'the best choice', over and above all else, regardless of price? If price is of no concern then there are plenty of custom coach builders that will design and fabricate a complete frame assembly for you so why did you stop with simply installing a Fatman package?

 

I'm glad that your car does everything that you need/want it to do and that the total cost was affordable to you. I also feel the same way toward anyone else with a street proven assembly that they could afford to build even if it is a lowly Dakota or Jag IFS.

[Dave72dt]

 

I like the terminology that a very knowledgeble man wrote on another car forum I contribute to... "The most dangerous man in the world is a farmer with a cutting torch and a welder".. 

Somewhat of a stereotype thought that suggests farmers should not be allowed to purchase, own  or come near torches and welders and I know there's supposed to be some humor in the statement.  Truth be told, there's any number of people who shouldn't be allowed near those tools regardless of profession.  I know of one farmer in particular who took a torch  and welder to a brand new piece of equipment, cut it up and made it better, obtained patents for his improvements and now produces that equipment on at least a national level and I believe international level.  We're not all hacks.

[Don Coatney]

I think it is all about ego.

 

If I wanted a car that drives like my Cadillac I would have bought another Cadillac. Instead I built my car on a budget with a flathead six cylinder engine and a 5 speed stick shift with disc brakes that stops in a straight line and will run 70 in the left lane all day long. My car suits my ego. I must assume that others have a different ego than me and that is fine with me as I am happy with my car, my torch and welder, sitting under my shade tree listening to the bull chew his cud.

[Andydodge]

One of the issues that we here in Oz have is that front clips, ie chassis clips are generally NOT allowed by the rego dept......I am not an engineer, however I do have a reasonable understanding of the various engineering requirements and to reduce bump steer was the reason for the 9" narrowed rack & pinion, the steering arms have also been modified to reduce the turning circle..........note that all this was done from 1973 to 1975/76  and the car has been driven approx. 35k miles since and there have been no failures..........here in Oz we have to use what WE have, lol..........I'd certainly like a Fatman clip, in fact spoke to Brent(?) 15-20yrs ago about getting one but the stubbling block back then and now was the rego dept..........you guys in the US don't realise how fortunate you are having relatively easy rego laws and availability of the parts and systems to update your cars..........lol.............regards, andyd     

[hkestes41]

I am with Don on this one. I have had Olddaddy's discs on my 48 for several years and can tell you it stops straight in Dallas traffic with zero incidents. It was my daily driver for about 3 years and Dallas traffic is not the friendliest for brakes.

 

Oh and I cruise the left lane at 70 with zero issues. Have made multiple 800+ mile round trips to the HAMB Drags on the interstate all without holding up traffic.

[blucarsdn]

Looks like I hit a real sore spot with many people.. I can truthfully say that I have seen far to many clabbered together suspension modifications under street rods..

A case in point... A good friend of mine, a very experienced DIU street rod builder has a very nice '29 A Ford sedan delivery which he built over 15 years ago.. The engine trans is a GM unit, the suspension is early Jag.. As I recall the build, the rack pinion had to be relocted to the front of the cross member to clear the engine.. A very common practice on Ford "A's/T's.. The calipers have to be modified, cut, welded and redrilled to accomplish this modification.. Old School type of thing..

My friend was recently cruising on the highway, returning from a car show.. All hell broke loose, the right front caliper came a-part, metal fatigue at the welds..My friend called me looking for early Jag parts to modify so he could fix his car.. I did some checking with guys I know, quickly found out that nobody in their right mind modifies calipres, etc., by cutting, welding etc., anymore.. Aftermarket calipers are made by several vendors to do tthe job.. My friend thanked me for finding him the info..

I have to agree with Andydodge in OZ.. In some respects we do have it made here in the States, a lack of govermental snooping into our car hobbies allows us to build vehicles that are safe, or unsafe, at our option...

Oh yes, many neat inventions have been made in this country by guys with "Yankee Ingenuity", a torch, forge and/or welder....

[HughForrest]

I installed a Cavalier rack on my original '38 Chrysler IFS & frame- no clip replacement was done.

 

I put in a slightly thicker sway bar, lower springs, & disc brakes at the same time as the R&P. While you wouldn't mistake the driving feel for a modern car, it is plenty satisfactory in a crowded freeway situation at speed, as well as getting in and out of parking spaces at low speeds. The only downside has been an increase in turning radius (but I'm working on that...)

 

If I wanted more modern handling on my '50 wagon I wouldn't hesitate to do it again. IMO a clip is just not necessary. Depends on what result you're looking for.

 

If you are an accomplished DIY'er you could do the Fatman (or Rusty Hope, I assume) R&P install in a long weekend. Doing the clip would be a lot more complicated.

[dndrodshop]

Got a Cavalier Rack on my own brackets and Power Disk Brakes I "fabbed" brackets/mounts for under $100.  Running for almost 15 years now.  Longest trip 3700 miles seem to work fine.

[Andydodge]

The problem with running a rack & pinion in a car that originally had a "normal" steering box is that the racks generally don't have the same "throw" of the tierods which allows the steering arms to be pushed sufficiently to supply a large turning circle........this is why I have had the steering arms in my car cut and shortened by an automotive blacksmith.......this guy knew what he was doing and I have not had an issue.......however another way to "reduce" the length of the steering arms is that which I have seem done by someone on this forum........the arms were mounted one bolt forward than the original setup, ie, the mopar arms have 2 mounting bolts that are originally used to hold the lower brake shoe pivots and also hold the steering arms........this setup had an extra hole drilled in the circular plate that holds the disc calipers on forward of the forward hole and then had the steering arms mounted on this new front hole and the rear bolt thru the original front hole...............you have effectively "shortened " the length of the steering arm as measured from the kingpin centreline to the eye of the tierod therefore allowing the rack & pinion "throw" to work on a shorter pivot point............voila!!!!!!.......you now have a shorter turning circle.......this is a neat and smart way of overcoming this problem......I wish I could remember who did this to give full credit........andyd

[chopt50wgn]

Here's a few pics of the Fatman stub attached and one with the motor in as well.

[casper50]

that looks pretty slick

[fstfish66]

nice looking job,,hard to tell where the  original  frame and fat man  stub  meet,,,nice job,,,question,was the radiator support already  in place on the stub or did you have to  figure out its exact location,,?

[chopt50wgn]

If you look at the frame without the motor, you can see the tab already there for the radiator support. It has the 2 big holes to attach the support. I liked the Fatman stub and it was not a big deal to mount and everything was already there even the bumper holes in the front frame horns.

I do have to say that my buddy who did the welding has been building hot rods and race cars for over 30 years and knows all the tricks. After it was all tig welded ,he did some other gussets as well. He's a bug on measuring 3-4 time before any cutting and he tacked everything first then did more measuring. When everything was on center and square, then he finished welded.