So I took my 1986 740 wagon to firestone and the mechanic said the wagon needs new front and rear link pins, where can I find these on the car? Also the rear vibrates when I drive the wagon above 70 or when I drive downhill off the gas. What could be the cause of this?

 

Vibration can be a lot of stuff. Start with tire balance, do all 4. Also could be a bad tire.Link pins...don't know...tie rod ends? Saying front and rear link pins I would hope he did not mean tie rods, or ball joints as they are front only.

 

Sway bar links?

 

speed related chassis vibration is almost always a bent rim or out of balance tire. the rear end is a live axle, the rear wheels pretty much HAVE to be parallel.

even with a sloppy front end, there's not really any vibration, just steering slop, maybe clunks on bumps and such, or uneven pulling of the steering wheel on hard turns under acceleration or braking.

badly worn sway bar ends will make clunks as you transition from left to right or visa versa.

badly worn steering tie rod ends will make the front wheels sloppy, like if you grab the wheel at 3 and 9 oclock and put some weight into rocking it back and forth, if you feel clunk-clunk, thats probably the steering tie rods. if you grab teh wheel at 12 oclock and rock it in and out, and feel clunk clunk, then thats probably the ball joint or mcpherson strut bushing. if you are in there doing the front joints, its a good idea to also replace the double-conical bushing that ties the front lower control arms together these are #11 in this drawing, that tie 9 to 7 or 7a. #19 is the ball joint,

 

So I replaced the ball joints, sway links, and tie rod ends. I grabbed the right front wheel and 3 and 9 then at 6 and 12 and only heard clunking at 3 and 9. I did the same with the left front and heard noises at both 3 and 9 then 6 and 12.

 

did you check your wheel bearings for play? worn out wheel bearings will clonk equally all the way around the clock.



put the front end up on sturdy jack stands, get a friend, one person rocks the wheel, the other person feels the various suspension joints to see where the play is.

 

i basically replaced nearly every joint on this 250k mile 92 740T wagon... I had my mechanic do it, although I bought most of the parts (mix of factory and superpro poly), and it cost a lot, but damn the car rode tight for years after.

 

the rear end on a 740/940 is pretty complicated, there's a thrust subframe with dual links where the rear axle 'pushes' on the car chassis, and it keeps it all snug and tight. this subframe is rubber isolated from the chassis AND from the rear axle, so its quiet and smooth.

 

and the rear springs and shocks and swaybar links...

 

 

btw, the oily oil pan, I found and fixed the leak causing that a few weeks later, it was the oil return pipe from the turbo, the gasket where it goes back into the block was torn. that little leak made a HUGE mess.