• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

CLUNK taking off with spirit

Share this page

RickB

RickB

Yoda
Offline
I managed to get under the car today and put a wrench to the shock mountings. They were all slightly loose but not so much that they would be making noise. They are all nice and tight now.
I don't have anything that shifts in the trunk to make the noise.

When I take off with any spirit at all I get some clunking noises, like someone is down there with a hammer whacking away.
From the drivers seat it usually sounds like it's from the right rear.

Taking off normally doesn't produce any such sounds, it's only when I give it a bit of power on startup. I can also make the sound on the shift into second if I hit the gas a bit harder.

Ideas about what's causing this?

Ah - I also put in an exhaust hanger and tightened up the pipe a bit, raised it up about 2 inches. Then I tried a speed bump that always scrapes and - no more scrape!
 
Check your U-bolts. Does the car "steer" when you get on and off the throttle?
 
ChrisS said:
Check your U-bolts. Does the car "steer" when you get on and off the throttle?
Click to expand...

I will -

no, it tracks true
 
Diff/axle shackle bolts?

Tranny mount?

Just a couple quick WAGs.

Is it like a "tramping" noise? i.e. is the "hammering" timed to axle hop?
 
DrEntropy said:
Diff/axle shackle bolts?

Tranny mount?

Just a couple quick WAGs.

Is it like a "tramping" noise? i.e. is the "hammering" timed to axle hop?
Click to expand...

Maybe, it's just when I "take off" if I'm applying any 'power'.
If I take off smoothly there's no noise at all.
 
The two things I suggested will usually only show up with spirited acceleration. Shock mounting bolts, too.

Lots of stuff under there has potential to thump under stress. If the shackle bolts are loose it may be possible to see "witness marks" in the area of the axle tubes up where the U-bolts go over the tube. Loose shock bolts can do the same... leave tell-tale "clean" outlines in the area around the body of the shock where it's flat against the chassis. Think: "snow angels" kind of effect.
 
Sounds like leaf spring wrap up from the hot Datsun motor Rick!! They were rated all the way from in the 60's to over 90 horse's. If you can't buy an anti axle tramp kit it would'nt be hard to make one.
KA
 
I'll jack it up again today and look for 'angels'.
How can I tell if it's the leaf spring thing?
Are there any examples online for making your own anti tramp kit, or where would I buy one for the Midget?
 
<span style="font-weight: bold">While I'm at it...</span>
are there any gotchas to watch out for in removing the spacers from the front leaf spring mounts? I assume I can just spray them up with PB Blaster and then remove the bolts. I guess there's probably something to watch out for with the spring tension like there was up front?
How likely is it that all the bolts / nuts will come off? I see the bolts for the front of the mountings are behind the seats - are they welded in place or will I need to hold them while working from the bottom?

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]The two things I suggested will usually only show up with spirited acceleration. Shock mounting bolts, too. [/QUOTE]

That's why I put the wrench to all 4 shocks yesterday.
They were not as tight as I would have wanted so I tightened them up. They were not loose enough to cause 'angels'.
 
Those nuts should be welded.
 
My 79 1500 did the same for a while, then it started doing it longer (and louder) after take off. Then the differential guts disintegrated.

With the new, diff, I replaced the leaf springs u joints and leaf bushings.

No noise after all of this, so I can't say that the diff was making the noise to begin with.
 
I just removed the spacers between the front leaf spring mounts and body.

I also tightened up all the U bolts and yesterday I tightened up all the shock mounting bolts.

I've just come in to wash my hands so I'll go out in a few minutes to give it a try out.
 
Well, I do notice the different angle with the back dropped just an inch. I like it.

It still clunks, it's definitely coming from something in the back. It does not do it if I start out smoothly & shift smoothly without putting a lot of power to the car.

It does not do it if I shift down 3rd to 2nd or 2nd to 1st.

I tightened up the u-bolts but I don't have a torque wrench any more and don't know how tight they should be.
I made them 'tight'.
 
Check the differential for slop and while you are under there, check the U-joints in the drive shaft for looseness!
 
The noises that Can drive you crazy!!

I had once changed trans mounts on my 1500 only to get a clunk everytime I got on it. Very upsetting. Of course I had the whole drivetrain out to change the mounts. Took me a few minutes. I removed the shfter boot and took off down the street while looking down at the shifetr area. hmmm. No more noise. Put the boot back on. Hmm noise is back. oooo.. got it. When I put the shift boot back on I used new slightly longer screws. The rear housing of the trans would just hit it every time. (Snapped the screw in half. Good 2 Go.)
 
Daniel Stapleton covers "axle tramp" in his book 'How to Power Tune Midget and Sprite'. I would'nt be a bit surprised if your local auto parts store or JC whitney does'nt have something. Seems like you used to be able to get a sort of extra leaf generic kind of thing to clamp on to any spring. Stapleton also says hard urethane pads and bush's will sometimes cure it.
Best luck! KA
 
Not a big job to check the u-joints but if bad, they usually will clunk even with normal driving. The symptom really sounds more like something larger like shackles, shocks (or shock mounts) or gearbox mounts. Maybe motor moounts or even spring tramp. Something under there is loose or worn though for sure.
 
I did look at my U-Joints while under there and they are nice and tight.
I've had plenty of U-Joints go bad in other cars so I remember well what that was like and this is different.

It doesn't happen backing up.
It doesn't happen taking off smoothly or shifting smoothly.

I'd be happy to add something to the rear suspension if it will make this go away.

I'll check my motor mounts again, it's possible the one that broke before has broken again. Is that going to cause a hammering noise in the rear of the car?
 
Inspected the rear spring hangers and mount? ... just throwing out wild guesses
 
Back
Top