My 7.25" rear is loosing a bearing or something. It keeps terrible noise starting about 40 MPH. I have been hunting a replacement axle and now find one. It is from '69 Valiant and my car is '66 Dart. Are those 2 equal in length? Is it a bolt on swap?

What kind of gear ratio can I estimate to find from '69 Valiant with /6 & manual? My original gears are 1:3.55 (170/manual) and I feel them a little bit too low for my super six'd 225/904.

jari@kuparikuviot.fi

Mark the pinion flange (where the driveshaft goes) and mark one of the drums or axle flanges. Rotate the wheel while keeping an eye on the pinion and count the number of times the pinion revolves during one revolution of the wheel. It's pretty easy to figure the ratio at this point; the pinion rotated somewhere around 3 times. A little less, it's a 2.94. A little more, a 3.23. Three and a half, 3.55. You get the idea. Good luck.

Mike


mkastelz@earthlink.net

You should have a direct swap there. Almost all of these axles were between 2.76 and 3.23, so you'll most likely get the shorter gears you're looking for. My '68 Dart had 2.76 from the factory, and most I've seen have that ratio. Usually the earlier A-body's have 3.23's or 2.93's.

Lou

You may want to check the axle bearings, that is a common cause for 7 1/4 noise.

The axle assy from the 69 will bolt right in, e-brake cables being the only big difference. See the "fast & easy" 7 1/4 swap tips below.

If you do swap to another ratio, please keep the 3.55 ring and pinion gears, (Don't turn them in as a "core") those lower 7 1/4 ratios are getting hard to find.
DD

Here is my "tried & true" 45 minute 7 1/4 swap procedure:

1) Jack-up and support car on chassis in-front of leaf springs. (get it up high)

2) Remove wheels, brake drums, drive shaft and axle shafts. (stay with me here)

3) Remove "U"-bolts. (wire brush or "chase" them with a threading die and lube with oil before starting to unscrew the nuts)

4) Now pry open the clips that hold-down the brake Hardlines, un-screw the "vent bolt" that holds down the brass junction block to the top of the drivers side axle "leg".

Pull the backing-plates off the axle leg's end studs and "slip" the axle assy. out from under the car, leaving the brake system "hanging there". (backing plates, e-brake cables, flex line & hardlines)

Slip the replacement axle assy. into place and re-install all the pieces. When done correctly, you will not have to bleed the brakes! I have done this job in under 30 minutes. (with air tools) and "roadside" in about an hour. (see the posts below on how I got so good at changing 7 1/4's fast! Search for "breaking suregrips")
DD

7 1/4s Go Boom!

I have to start with these axle bearings. I guess I cannot test them. Maybe they don't keep that noise unloaded even when they're faulty.

I has been long time since I have seen 7.25" in pieces. Those bearings are threaded to the axles and locked with some kind of locker ring? Are those locker parts still available?

I think I need professional help to get them off and new installed, so I maybe lift my car, remove axles (after I have found those parts) then go to the nearest Chrysler dealer repair shop and so on.
:
: If you do swap to another ratio, please
: keep the 3.55 ring and pinion gears,
: (Don't turn them in as a "core") those
: lower 7 1/4 ratios are getting hard to find.
: DD

You said it. I just change my mind to keep them I they're possible to fix less noisy. This combination is quite sporty now. I can get the maximum allowed highway speed at the slip roads and an unofficial traffic light test has shown that this combo is faster than stock C-boby (Monaco) with 440-4bbl.

JKKo



jari@kuparikuviot.fi