Any ideas as to WHY the differential on the new axle on my 78 is hitting underneath the car under medium acceleration? It doesn't smack when I accelerate from a stop slowly, but if I give it some gas to get going with some decent speed, it seems to "torque" upwards and smack against the rubber bumper right above the differential.
I did notice that it seems to point upwards just SLIGHTLY more than the old axle did, about 1/2", but does it really make that big of a difference when it comes down to the geometry of the drive-train?
Now the question of "how do I fix this" comes up....
Are you sure you have the rear sitting squarely on the spring perches? There is an oval or round hole in the perch on the housing that has to line up with the perch on the spring. And yes 1/2" makes a difference in the geometry. Other than that little snag, how's the new gear?
Thank you so much Jimmy! I was really hoping you would see this thread! I knew that you out of all people would know for sure! :)
I will see if I can pull some from a 73 at the junk yard in Caldwell, depending on the price. Otherwise I'll be shooting Fred a PM!
Now, other than the little snag, the car is SO much more fun to drive! :D Squealing the tires is a first for me, never been able to do it in the 78 until now! :) I should really control myself though, don't want to have to buy new tires in a few months! :P
I love that I can drive 35 mph in fourth gear, and the fact that I still have power in all gears when driving around town! I'm having a bit of fun trying to learn how to drive the car again (when to shift, how fast I can go in each gear), but I'm loving it! :D
Also, the new rear fixed a problem I had suspected was due to the old rear was causing. When starting from a stop, the car used to drop way down in RPM, then slowly gain speed. With the new rear, the clutch grabs and the car takes off! WHEE!!! :D :fastcar:
http://www.bob2000.com/pinto.htm (http://www.bob2000.com/pinto.htm)
according to this page the spring perches do not interchange. :(
Should I just cut my 78 perches to fit?
Dave, I'm lost here. If you have a mII rear end it should bolt right on your 78 spring isolators. I eliminated the rubber stuff on my '72 and used Racer Walsh lowering blocks and aftermarket u-bolts to get around the round/oval situation. JT
72pair: I'm using a 6.75" rear with a lower gear ratio now. It's a 73 axle assembly on a 78 model Pinto.
The axle perches on the 78 have oval spring isolators, the axle from the 73 has round isolator holes. I was thinking I could just remove the excess rubber with a die grinder, but then there's the metal that flanges upwards that I would have to grind down as well.
I can get a pair of 73 perches from a junk yard here for $30.00 (for the pair), and put spacers between the shock mount plate at the bottom and the perch plate on the top to make up for the space where there shouldn't be a fifth leaf. I just really don't want to cut up my 78 spring perches for when I have to swap back to the 78 axle. I cannot find ANY parts for this 73 axle! :(
They won't interchange?? ??? I don't understand what won't interchange. I've used both kinds. Just use the perch and rubber spacer with the round hole. All you need is the top part. Other than that they are exactly the same. I've got rear ends out back in my "Pinto junkyard" that I have tie strapped the correct perches to, and have swapped rears around many times.
Here is a direct quote from that website:
The spring perches do not interchange, because the 72 has 4 leaves and the 75 has 5 leaves, making the spring perches different depths. In order to make the swap, the helper leaves from the 75 had to be moved over to main leaves of the 72. From what I understand, the main leaves on the newer cars are different than those of the early cars, and do not interchange, due to their different lengths.
Quote from: 71pintoracer on April 03, 2010, 06:36:20 AM
They won't interchange?? ??? I don't understand what won't interchange. I've used both kinds. Just use the perch and rubber spacer with the round hole. All you need is the top part. Other than that they are exactly the same. I've got rear ends out back in my "Pinto junkyard" that I have tie strapped the correct perches to, and have swapped rears around many times.
I agree! From
the website: "The spring perches do not interchange, because the 72 has 4 leaves and the 75 has 5 leaves, making the spring perches different depths. In order to make the swap, the helper leaves from the 75 had to be moved over to main leaves of the 72." is non-sensical gobble-de-gook!
I think that the author is confusing
(http://www.trail-gear.com/images/3holeperch-600.jpg)
with
(http://www.mustangdepot.com/onlinecatalog/images/Suspension/opt-rsp.jpg)
http://www.mustangdepot.com/onlinecatalog/Suspension/spring-perches.htm (http://www.mustangdepot.com/onlinecatalog/Suspension/spring-perches.htm)
Mike
I see! Now I need to stop saying "perches" when I talk about the plates the axle sits on! o.O