Tap, tap, tap, knock, knock

[X5chemist]

Recently a tap started in the rear. You can hear it only at low speeds. The slightest movement will cause it. I drove the rear up on some 4X4 wood ramps. I used a big pry bar trying to find the tapping source. It's not a suspension part. Not the battery. I even took out the back seat. I found a quarter.

I checked play on the driveshafts. Nice and tight there. The tap seems to be above the differential. Behind the seat. Cargo forward area. It's like something is rolling around. Or loose. It should be obvious. I can't see it though. Next week, I'll remove the spare tire and associated tools. With everything out of the cargo area, I may install the hitch too.

Any ideas on what's causing the tapping noise?

[Henn28]

Maybe a loose shock, or air/spring at the top? I had a terrible tap after I installed the lift and it was because the tops of the shocks were not quite secure (bolts were slightly too long).

Its not the sound a bad sway bar link makes, is it? My experience with bad links is that they knock at low speeds. Definitely more of a knock than a tap, however.

Beyond that I'd say pulling the rear spare tire area apart is your best option.

[haigha]

I hope the solution is simple!

I was concerned when I replaced the taillights that a nut or a tool would fall into the abyss and I'd have a rattle forever. My preventative solution was to put several microfiber cloths at the bottom of the tight space between the DSP unit and the taillight. They saved my Wera mini-ratchet from falling where it might have been unretrievable.

[X5chemist]

Henn28, I'm thinking the same thing. Top of the rear shock may be tapping. It should have a lock nut though. I'll remove the cover and check.

[andrewwynn]

Originally Posted by haigha

I hope the solution is simple!

I was concerned when I replaced the taillights that a nut or a tool would fall into the abyss and I'd have a rattle forever. My preventative solution was to put several microfiber cloths at the bottom of the tight space between the DSP unit and the taillight. They saved my Wera mini-ratchet from falling where it might have been unretrievable.

I lost a screw forever down in the trunk abyss on my e53. Also several nuts and bolts down the engine bay! I'll try to remember the rag idea that's very smart

[andrewwynn]

Many suspension parts are preloaded where you can't find the loose joint unless you take off the spring pressure.

That said. Morse code light taps usually either sway links or tops of shocks. It's easy enough to take off one side of a shock to make sure they move smoothly and feel for wiggles.

Sway link should be very difficult to twist buy hand, every failed one i could rotate by hand pretty easy.

I have a similar tap front right on my e70. I didn't see anything in the ball joints so I'm suspecting top of shock tower bearing or mounts.

[X5chemist]

The sway bar bushings are okay. Previously, I checked the new sway links. They are tight. I took out all the sound deadening items. Cargo liner and blanket. I'm leaning towards the right shock mount area. The shock feels tight at the control arm. Maybe the shock bushing has moved out of position. I'll check it this week.

[andrewwynn]

The differential mount is a possible source

[X5chemist]

HMMM, I'll check them. From pictures, I see only three bolt locations. Three really? Two front by the guibo. One big one, top left side. I'll check the bushing with a light and mirror.

The Curt S019 hitch looks easy to install. I'll tackle both projects on Thursday.