Don Carter

I've held off asking for help here on this, thinking I'd eventually figure it out, but I've gotten nowhere, so here it goes...

I did the motor mount job back in December and starting immediately afterwords I've had a popping/knocking noise coming from the front when driving slow on bumps, or turning in parking lots. Don't hear anything at speed.

I felt a small amount of play in the front bearings and tightened them slightly but that that didn't fix it. I've checked all the bolts that were removed and they are torqued properly. I do have a torn CV boot that needs replacing, but the noise is coming from the front.

It has to be related to something that was taken lose and reinstalled, or the fact that the engine is sitting higher.

Did find one post where someone had a noise and sprayed WD40 on the new mounts and that fixed it, but it didn't work for me.

I had Herman and Ole helping me who had both done the MM job before, so I feel pretty confident we didn't make any big mistakes.

When I look at the suspension and try to move the wheels around while jacked up, I don't see any significant movement in any components, although there is some play and the rack does move slightly with it's original rubber bushings. I have not had it aligned yet thinking I may have to replace something and it's tracking perfect.

I did install the washers included with the mounts by the way.

Any ideas?

Mrmerlin

most likely is that you have one of the locator pads turned on the motor mount and this is hitting the crossmember when the engine/car hits a bump. You may be able to move it with a prybar and the car nose off the ground

Don Carter

You mean the piece with the retaining hook?

I could try to get some pics of the mounts.

Landseer

Hard to say. If you don't find it with suggestions above, then here are two things I've run into under there:

I've had one left side MM bolt, when left uncut, contact the steering rack tubing, so check that.

Also, on a different car, the right-side front stabilzer bar mounting bolt had worn on the shoulder where it holds the bar, allowing movement and lots of noise, even though it seemed tight.

Don Carter

Thanks for ideas.

The bolts were already trimmed on the mounts I received (thanks Roger).

Not sure I fully understand the worn bolt, but I'll take another look at it. Sounds like a possibility.
Stabilizer bar = Sway bar, correct?

Calgary Ole

If I remember correctly, the bolts were cut and washers were supplied.

Landseer

Some are, some aren't and some aren't cut enough.

The first two sets I installed were before he knew it could be an issue. I took photos to show where it interfered. The third set was ok as-is, but one of the two solid mounts was a different brand / look --- I used it anyway. The last set I bought needed additional trimming.

Yes, I meant sway bar. Its held to the down link by one bolt on each side. One was run loose apparently. I torqued it, still had noise. It had actually worn on the shoulder so that it didn't hold right, even torqued, giving the sway bar room to move.

jeff spahn

That was me with the squeak that was fixed by WD 40. We also had a sound in the engine bay that was the steering knuckle hitting the PS hose. It got bent when we lowered the rack. You could check that.
Please send pics of how your engine is sitting in relation to the crossmember with the washers. I'd like to see the difference.

Mrmerlin

yes its the retaining hooks on the lower mount pads that can sometimes hit the crossmember

Don Carter

Thanks Jeff. I'll check the PS lines again, but this noise sounds a bit more solid and loud than a squeak.

I didn't do a lot of research on the washer/no-washer debate, just saw they were included so installed them. Probably don't make more than an 1/8" difference in height.

Landseer

With the right light and orientation, you should be able to just barely see the end of the bolt near the drivers side of the steering rack to determine if there is contact there.

Other contact points could be the bowden and vac line at the top of the bell housing or a heat shield in that area.

Again, all that said, I always check what Stan suggests first.

Mike Frye

OK, so when you did the MM job the car was lifted by the jacking points, right? So the suspension was completely unsprung while you did it?

What about the upper ball joints? Are they new or rebuilt?

There was a thread on here recently where it was discovered that if you used the rubber cups that came with the upper BJ repair kit from Roger, it could make a popping noise going around turns or at low speed. Is it possibly the sound of air popping into or out of the upper ball joint cups?

Just a thought.

For troubleshooting, maybe get some of those wheel dollies so you can turn the wheels with the weight on the suspension and see what's going on? (no affiliation, never even used them but it looks like the right way to find this problem)

Don Carter

Yes car was lifted by the jacking points using PorKen lift bars.

I didn't replace the ball joints. I think they are original.

Don Carter

Took another look underneath this evening and took a few pictures. Not too thrilled about showing off my grimy underside, but for sure the cam end seals, which are leaking horribly, are on my to do list.

Both MM bolt ends are at or below the level of the nut, so definately not hitting anything.

It really looks like the passenger retaining hook might be the issue (first pic). Just one bolt holding it on, so thinking about removing it and seeing if that fixes the noise. If it does, I could try to reshape it so it's further from the cross member. Not too likely brand new MM's are going to fly apart unexpectedly.

Don Carter

Nevermind, the hook is welded to the MM bracket. No easy way to remove it. Looks pretty strong, not sure if I'll be able to bend it away from the cross member. Don't see any other way to move away or adjust it's position.