knocking problem

[Jimbo]

OK just got done putting on rear springs and new
wheels and tires.Took it out for a test drive and every
time I hit a little bump or small dip I hear this clunk
coming from the back.At first I thought I did something wrong
when I put in the springs,so I redid the whole thing
again checking everything twice.Took it for a ride again
same thing.Sounds like the muffler is loose ,but it isn't.
I tied down the tube going to the gas tank.It seem to be
loose,but it didn't help.Any ideas? The springs look like
they are seated right.I can't see anything loose under there.[xx(]
[xx(][xx(][xx(][xx(][xx(]

[DBROWN03]

did u cut your bump stops in the rear?

[Jimbo]

Yes, it sounds like something is loose,but I can't
find anything.

[CREWZIN]

Jimbo,

I'm sure this was just discussed somewhere but...do you have a larger than normal exhaust. A few of us that do and have lowered the PT have had the bump. It may look like a lot of room where the exhaust goes over the rear axle, but some up found that the exhaust pipe was actually hitting the axle when going over bumps. The way I stopped it was to have an exhaust shop put an extra exhaust hanger right near the axle and pull the pipe up maybe an inch and secure it there. Cured mine. Hope it helps you. If you can get under the car, look to see if there's tell tale signs of the exhaust hitting the axle (scrapes on the pipe or top of axle).

[Jimbo]

CREWZIN, I'll check that out tomorrow.Right now this thing
has given me a headache[xx(]Sounds like you could be right,
One other question,I put on American Racer Snipers and while
looking for my bump I noticed that the rear brake lines don't
have much clearence between the wheel and the line and the
weights for the wheels are on the inside so there is no room
at all or next to nothing.problem?

[CREWZIN]

No problem at all...unless the brake lines are rubbing. The brake line and wheel move up and down together so if it's not rubbing now, it shouldn't rub later, but I'd keep an eye on it.

[Mike-in-Orange]

Jimbo, two things to look for:

1. Under the car on the passenger side inboard of the rear wheel well is the fuel line, which runs pretty close to the wheel well liner. In some cases this can be the cause, but not always. I thought it was with mine, but it wasn't.

2. Get under the car and take a close look at the exhaust directly above the rear axle. Look for any sign of contact. I mentioned in another thread that the guys at PT Tuning told me a 2" drop on the rear of a PT seems to just exceed the limit of available room. When I first looked at mine (BTG cat/back duals and GoldLine springs) it looked like there was a ton of clearance. Bouncing up and down on the back end just didn't look like it could move enough to cause the clunk, but it could and DID.

I just got mine fixed today using basically the same method Crewzin described. Take a good careful look, I'll bet that's the problem.

[Jimbo]

Mike and CREWZIN you were right.I really couldn't see any
marks on pipe or axle so I got a small piece of rubber
and 3m taped it to the top of the axle and went for a ride
down this piece of crap road by my house and no more clunk.
I have a friend that works at a muffler shop.I'll see if he can
come up with something. Thanks for the help.[^]

[quicksilverdon]

Yes, a little-advertised "benefit" of aftermarket exhaust in combination with lowering.

[CREWZIN]

Hey Jimbo,

If the 3M tape and piece of rubber fixed the bump, why not just leave it there? [:I]