Help needed with front end noise & how a shock should behave please

[klein444]

I have a 96 P71 with 202K miles on her and still running strong. About 4 weeks ago I noticed a bumping type noise coming from the right front wheel area. It has gotten progressively worse since then.

We live in a rural area and our roads beat you up pretty hard for the last few miles home everyday (and leaving home too).

The noise is best described as a rubber dampened metal to metal thud. Not so much a straight out metal to metal clank. It is subtle on slight bumps and loud on the very rough sections. Sounds like it is coming from the upper area of the passenger front wheel.

I poped the hood and hunkered down on the fender on each side and on the drivers side it came back up after being presssed down. On the suspect side it behaved almost the same except I noticed the top mounting bolt and bushing for the front shock moved around as I pressed down on the fender and released.

Repeated and it happened every time. So I assumed it was missing its bushing that would be under the shock tower . Pulled the shock this weekend and found the bushing was there, worn but present. Looks like it is made in a cone shape. I looked up through the spring and you could see that the underside of the shock tower was 'polished' to a nice silver color in an oblong/circular shaped fashion as if the shock has been moving around and certainly not firmly in place.

I did not have the $ for new shocks so I fashioned a make shift extra bushing and pressed it onto the shock before reinstaling. Put the top bushing on and secured it to specs. By the way the top nut was not loose prior to me removing the shock - I did check that first.

So just how should a shock behave when removed?

I took the shock to my bench and was able to compress it by hand. It barely managed to extend itself. If I had timed it I would say it took a good 15-20 seconds to crawl back to a full extension. I put it upside down and compressed and extended it a few time to purge it and that seemed to help a little, however, it was still very easy to compress and very slow to extend. Is that a shot shock or normal for a motorcraft p71 shock? I'm used to mountain bike forks that have a rebound cycle much , much faster.

With the extra bushing in place I reinstalled it and that took the noise down a bit, however, still there and still very loud on the country roads.
I visually inspected the remaining components of the steering system and control arms and did not see any obovoius wear or excessive play when moved around. The car tracks on the road in a straight line and brakes with no hands on the wheel in a straight line. It steers fine and handles great (based on how I am used to it handling for the last 6 years).

So ... after writing this novel for everyone Does it sound like the shock is bad? Should I also be looking for something else in that area - If so what?

I appreciate any help or advice. Pay day is next week and I'm ready to get her fixed.

~GOD BLESS~

john

96 P71 with 87 Ebbtide former Game Warden boat 115 Merc

[MagicRat]

Your shock damping sounds fine. All shocks are MUCH easier to compress than they are to extend, because it's the spring rebound (extension) that needs damping. Rebound damping is always very strong and stiff on auto shocks, especially front shocks, due to their placement location on the control arm.

Spring compression does not require much damping.

Also, because the shock extended on it's own, it still has the gas (nitrogen) pressurized charge. When shock damping wears out, it seems the pressure is the first thing to go.

To me, it seems like your bushings are just pooched. If you know someone who has some old shocks lying around, you might be able to transfer the bushings. Otherwise, though, you need 2 new front shocks (it's best to replace them in pairs. )

[klein444]

Excellent! I just picked up a pair of motorcraft P71 shocks from the Ford dealer across the street from where I work for $79.84 tax included (part #ASHV-1038).
Plan on putting them in tomorrow. Based on how the new bushings look I bet I had at best 10% of the bushing left on the shock in question.

Interestingly the motorcrafts that are on the car now are stamped as made in Japan and the new motorcrafts are stamped as made in USA.

I'll also check out the sway bar end links and the ball joints while under this weekend.

~GOD BLESS~

john