belvedere666 Posted March 25, 2016 Report Posted March 25, 2016 Just an FYI: I came across a 1950 Plymouth suburban Rear axle. I have a 4 door sedan. Same gears as mine (3.90) but it had newer brakes, both right hand drums, and had been serviced recently. i figured i should just be able swap the rear end out and it should be good to go. WRONG. it turned out that the suburban axle was 2 inches shorter in width. Backing plate to backing plate the suburban was about 52 inches and the sedan was 54. doesn't seem like it would make a lot of difference but it pulled my wheels in an inch on either side, and the spring perches didn't quite match up. they are closer to the backing plate, which makes up some of the distance but they aren't quite a match. i should have measured it before i put it in! but i figured, they'd be the same, as i couldn't find any info that specified that they are different axles. this was quite a difficult job for one person. then i had to swap it back out, by myself. At this point, i guess just take the brake stuff off and get rid of the rest. Quote
Plymouthy Adams Posted March 25, 2016 Report Posted March 25, 2016 odds are it may have been a 49 axle......they are two inches more narrow...it is the most narrow of the era 46-54 2 Quote
belvedere666 Posted March 25, 2016 Author Report Posted March 25, 2016 odds are it may have been a 49 axle......they are two inches more narrow...it is the most narrow of the era 46-54 there's a number stamped into it "1141544-5" with a "9-22" above that. i looked into that number but couldn't find anything that gave me any real info. Quote
dpollo Posted March 25, 2016 Report Posted March 25, 2016 PA is right. The gear set is the same as your 50 so are the brakes but the axles and housing have to be from a 49. Most axle shafts from 37 to 48 will interchange. 49 is unique 50 to 52 will interchange and 53 to 56 are the same length but use a finer spline. April 1 is coming up fast . Looks like your car won this round but that is how the game is played. The parts book shows the same axle shaft for all Plymouth models in 50. Quote
Plymouthy Adams Posted March 25, 2016 Report Posted March 25, 2016 unfortunately over the years, we as new owners really do not have a full history of what a PO may or may not have done to the vehicle...many parts are used as they can be substituted but still be just that tad bit off between production models Quote
belvedere666 Posted March 25, 2016 Author Report Posted March 25, 2016 is it possible to change the gears inside without swapping the axle? the guy i got it from said that it handled really well on the highway at 65 with the original flathead 6. i haven't taken my car out yet so i don't know how it's supposed to drive but i hear they don't do well. Quote
Plymouthy Adams Posted March 26, 2016 Report Posted March 26, 2016 do not change the gears individually, change the pumpkin/hoghead with the gears intact to your original axle..brakes should transfer also...do watch for the shims per side as they are what sets the free play..read your repair manual..it is not a difficult job by any means 1 Quote
Don Coatney Posted March 26, 2016 Report Posted March 26, 2016 Where did you hear they don't do well? Many on this forum have no problem driving at that speed. Quote
belvedere666 Posted March 26, 2016 Author Report Posted March 26, 2016 Where did you hear they don't do well? Many on this forum have no problem driving at that speed. before i bought the car i was talking to my uncle, who has the same car, and three people i know, one had a 41, one had 51 and one had a 50.. they all told me to change out the rear alel unless i wanted to max out at like 45 on the highway. were they mistaken? Quote
Niel Hoback Posted March 26, 2016 Report Posted March 26, 2016 Yes, they were and are mistaken. I drive 60 with room for more. Quote
belvedere666 Posted March 26, 2016 Author Report Posted March 26, 2016 Yes, they were and are mistaken. I drive 60 with room for more. Yes, they were and are mistaken. I drive 60 with room for more. that's great to hear! Quote
dpollo Posted March 26, 2016 Report Posted March 26, 2016 I have never had any problem with driving 55-60 in a car with 3.9-1 rear axle ratio . The addition of an Overdrive makes highway driving at 60 to 70 a breeze. 30% reduction in rpm. That is not to say I would recommend traveling at those speeds unless everything is in good shape. Years ago, we would take a car which had never left the city and flog its butt down the highway at excessive speeds. Disastrous results, often. Quote
wayfarer Posted March 29, 2016 Report Posted March 29, 2016 were they mistaken? Generally, they sound like they are well past the point of being done.....the noise is usually traced back to the 4-blade fan... 1 Quote
mopar_earl Posted March 29, 2016 Report Posted March 29, 2016 I recall reading several different opinions that the Flathead doesn't like sustained high rpms such as driving 65/70 with 3.90 gears or lower with no overdrive. I don't recall the recommended rpm. Under 3000 I believe they said. I'm guessing do to the long stroke. No you won't max out at 45 mph unless your semi-auto isn't upshifting. Earl 1 Quote
Merle Coggins Posted March 29, 2016 Report Posted March 29, 2016 I've run my engine on many extended trips at speeds over 3000 RPM with no ill effects. Merle 1 Quote
CoronetGuy Posted March 29, 2016 Report Posted March 29, 2016 I cruise mine at 65 all the time 1 Quote
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