Squeaking Sound (rearward) Under Acceleration? **Solved**

[Oblithian]

While driving around the coast I noticed my car (1975 280z 2+2) has started making a repetitive spring-like squeaking sound that gets faster as you drive. But it only makes sound under acceleration, and only when driving forward. Also, it is less noticeable at higher speeds. However, it isn't that loud. So, it could be that it stops, or it could be that the engine and road noises drown it out. It sounds like it is coming from the PS rear-quarter? The car does not squeak when going over bumps or when I bounce the corners of it.

I am on a trip at the moment so I can't examine it. Does this sound familiar to any of you?

At this point I am thinking, brake... maybe axle related?

Edited September 8, 2021 by Oblithian
Resolved

[NewZed]

Sounds like a u-joint.  There are two on the each side and two up the middle.  Look for dry damaged seals, and rust powder.  Pry them around with a long lever, look for movement.

 

Could also be the sliding portion of the half-shaft itself.

[Oblithian]

Thanks for the suggestion, I have replacement u-joints from... several years ago (I wanted to have them handy if/when they went. The driveshaft u-joints had gone before I bought the car).

If it is the shaft itself... Then I guess I have an excuse to make the 300ZX upgrade.

[Oblithian]

Update: So I can't say for certain what is causing the sound, but after having inspecting all the parts for play, I can say the wheel bearing needs replacing.

So... Maybe it is an early warning sound? Or maybe the bearing is fine and there's just too much play in the hub.

[heyitsrama]

Just a heads up on the u-joints, i ended up ruining a pair of half-shafts after trying to replace the u-joints myself. IIRC the balance of the shaft is done by the different thickness c-clips that are used to lock the ujoint to shaft.

 

IMO if you need to replace the u-joints consider having a shop replace them with some Splicer ujoints as the shop should have the different thickness c-clips to balance the shafts after.

 

I think the driveshaft does not have replaceable ujoints for the 280z models, in that case a upgrade/replacement should be sourced.

[Oblithian]

On 7/27/2021 at 12:24 PM, NewZed said:

Sounds like a u-joint.  There are two on the each side and two up the middle.  Look for dry damaged seals, and rust powder.  Pry them around with a long lever, look for movement.

 

Could also be the sliding portion of the half-shaft itself.

SOLUTION: You were correct, the sound was the outer U-joint of the PS axle-shaft. When I pulled them it was very obvious it was bad. I replaced both of them and the sound is now gone.

(The hubs also have too much play. We'll see if it's the spindle or the bearings, or if it just needs tightening).

 

I will add the video or images here when I get around to it.

Thank you all for your help.


P.S.

Quote

 I think the driveshaft does not have replaceable ujoints for the 280z models, in that case a upgrade/replacement should be sourced.

True, in some years the propshaft/driveshaft u-joints are listed as 'not replaceable' like 1975 (mine). However, they can be replaced yourself if you can track down the right parts using measurements, or just have them done at a driveline shop. I have done both. There is a video on me doing that, but it's not immediately relevant to this thread so here is one on that subject for anyone coming to read: https://forums.hybridz.org/topic/100835-280z-driveshaft-u-joints-irreplaceable/

 

Edited September 9, 2021 by Oblithian
Typo

[Phantom]

How were the axle shafts themselves?  Were the u-joint pockets snug or were they a bit loose?  They should be snug or your problem will come back quickly.  I just had to replace the u-joint on the driver side half-shaft only to discover that it took locktite on the axles to get them to stay put as they were worn.  250K on the car and the last 50K with an LS1.  Passenger side still has original 1977 factory u-joints.  That is a really scary thought at this point.  CV joint halfshaft upgrade in the near future.