Replacing rear leaf springs ?

[DougME]

Hi All, I'm contemplating replacing the rear leaf springs on my 1962 TR-3B. Reason is very rough ride and I suspect the springs may be bottoming out on larger bumps (Maine). I know the shocks are to blame as well and I've been changing the valving in the shocks, (more to go)( hints?) but I can't help but think new springs would make a big difference. What to do? Has anyone done this and been glad they did it or was the difference barely noticable. The removal process looks like it may be very tough, the front pivot bolt especially. Hints?,advise.

I've measured the ride height of my car from the center of the wheel to the top of the arch of the wheel well. It is 13 3/8", anybody else have similar dimensions? The rubber snubber attached to the bottom of the axle rides about 1 1/8" above the frame of the car.

Thanks for reading guys. Vrooooom, Doug

 

[TR3driver]

The rubber snubber attached to the bottom of the axle rides about 1 1/8" above the frame of the car.

Well, you certainly wouldn't want it any closer than that, so the springs sagging is not likely to be the problem. Note that these cars always rode hard compared to a more modern suspension design, it's simply the nature of the beast.

However, the springs may still be causing the harsh ride, if the leaves are rusted together. They have to move to let the spring flex, so enough rust in there makes for essentially no suspension at all.

Removing that front pin isn't a lot of fun, but I've had it out on several TRs now. In fact I'm planning to replace the rear springs in my daily driver soon (when I install the rebuilt axle as well), but haven't yet decided whether to buy new or try a used pair of late TR4 springs that are hanging in the garage.

First thing to do is remove the nut & washer, then soak the entire area in your favorite penetrating oil (PB Blaster is mine, but Kroil works good too), and leave it set. I repeated that, along with some love taps from a BFH (to set up vibration and maybe help the oil penetrate), every few days for several weeks.

There is a tapped hole in the head of the pin (on the inside of the frame rail). IIRC it is 5/16NF. Clean out the threads, first with solvent and then with a bottoming tap.

Get some hardened threaded rod, nuts and heavy flat washers (got mine at MMC ) plus a heavy socket that will just fit over the head of the pin (and the little tab on the frame that keeps the pin from turning) and an assortment of short (1-2") spacers that will also fit over the pin. Cut a short length (about 4-5") of the threaded rod, and double-nut it to tighten into the hole in the pin. Remove the nuts, lube the threads and add the socket, heavy washer and a nut. Tighten the nut until the head of the pin hits the socket. Then take it all back apart, inspect the threaded rod & nut for damage (I had to replace mine several times), add a spacer and do it again.

If the pin won't move before the rod strips, you can try cutting through the end bushing on the spring and the pin. With the spring out of the way, you can either try again with a new length of threaded rod, or there should be enough room to drill into the pin (which will help loosen it even if you don't drill it out all the way).

Of course this is a project that can quickly go from bad to worse, if you either pull the tube out of the frame or the threads out of the head of the pin. Worst case, you'll need to cut out the old tube (possibly with the old pin still inside it) and weld in a new one along with some reinforcement plates.

 

[Andrew Mace]

However, the springs may still be causing the harsh ride, if the leaves are rusted together. They have to move to let the spring flex, so enough rust in there makes for essentially no suspension at all.

Just a crazy thought: what about just soaking both springs in oil (motor, gear, or penetrating), and see if that helps? The Factory Workshop Manual recommends cleaning the springs and then "...brush the blades at their edges with engine oil, this will allow sufficient oil to penetrate between the leaves and provide inter-leaf lubrication.
"Lubrication of spring blades is chiefly required at the ends of the leaves where one presses upon the next and where the maximum relative motion occurs."

A similar recommendation is made for the single transverse leaf spring on Heralds and Spitfires, and I know from experience that it makes a significant difference in ride quality on those cars.

Just sayin'.... :laugh:

Edit: Oh, you do want to keep the oil away from rubber bushes and such!

 

[FordFiesta]

Oil works. In the 20s and 30s, oiling the springs was a regular thing done at service stations for a small fee. On the TR, one way to make sure the oil gets in there is to spread the ends of each leaf apart from the one it's next to by using a hammer on an old screwdriver you don't much care about -- to forcibly spread the leaves apart. A squirt oil can with a long flexible nozzle is then your friend. Kroil (etc.) penetrate well, but don't offer residual oiliness.

 

[tdskip]

Just went through this on the MGC and it required taking them totally apart, cleaning them, painting them and then replacing the liners. Totally worth the effort however.

 

[TR3driver]

and then replacing the liners.

TR3 didn't originally have liners, however MMC sells some UHMW PE tape that works well. I already added it to the springs on the TR3, and will be doing it again for the new ones.

 

[TomMull]

Just went through this on the MGC and it required taking them totally apart, cleaning them, painting them and then replacing the liners. Totally worth the effort however.

FWIW, Used to do that on trucks when we replaced individual leafs. Left the main leaf right in place. Might be possible to do on TR to avoid messing with the front pin but I've not tried it. Tom