Trailing arm knock

[PhilNW 40]

Hi Gavin

 

Can yo add a bit more detail as to what was connected and what wasn't for each scenario?

 

Originally you gave the impression that the knocking was only when the ARB was connected, now you are saying with the TB reinstalled there is a knocking . without the ARB?

 

[Gavin Waddell 18]

Sorry. 

Took out the the ARB and and left the TB in situ and it knocks

Took out the TB and ARB and it still knocks.

 

I reassembled every think and it seem to be all nice and tight and didnt knock when i moved it by hand, then did a test drive and it knocks.

 

[PhilNW 40]

Struggling with what it could be at the moment.

 

Something has worked loose after the 1000 miles

 

EDIT

 

Did you try bouncing the rear of the car?

 

 

 

 

Edited June 30, 2023 by PhilNW

[Gavin Waddell 18]

I checked all the bolts and every thing is tight.

[jord294 87]

Did you fit new bushes?

[PhilNW 40]

Are you sure its the suspension and not say the rear subframe mounts/bolts or exhaust?

[Gavin Waddell 18]

It had the teflon bushes from BBM fitted and new grp n sandwhich bushes.

Its the beam, car is on axel stands and when i move the trailingarm up 1cm in a shost sharp movement in knocks, like i said even with everything disconnected.

[PhilNW 40]

Any chance you can post a short video 

[Gavin Waddell 18]

I will try this aftenoon, 

[jord294 87]

Have you got the 4 bolts for the supports in right way around? Lock nuts to centre of bot floor.

 

I know ow people who sell wrong spec aftermarket bolts and if fitted wrong way around the excess thread catches on trailing arms 

[Gavin Waddell 18]

9I used the original bolts, i wanted to stay as original as possible. 

 

Here a 2 videos of the knocking in action I took out the ARB, but not the TB as then I would have to reset the ride height and i couldnt be arsed as it would ahve been the 3rd time this week.

[Gavin Waddell 18]

[Gavin Waddell 18]

Voila, hooe that helps.

[PhilNW 40]

Quite a lot of movement but I get the impression that the movement happens before you get resistance from the TB and the knock happens as you get resistance from the torsion bar. Is that about right?

 

 

[Gavin Waddell 18]

It's about right.  However to make it knock i apply more of a laterla forec than a rotational force.

Before taking out the ARB, i tried to make it knock, but it wouldn't, as if the ARB was holding everything together, but when i drive in knocks like crazy.

 

What bugs me is that before refurbishment of the beam nothing knocked, the only thing i changed was the bearings. And the other side doesn't knock.

 

Yesterday i tested the beam buy sliding my spare shaft and i applied lateral and rotational force and no knocking.

The trailing arm increases the levarage  movement.

[PhilNW 40]

If knock more due to lateral movement, have you adjusted the stud on the opposite end of the TB?

 

http://www.miamistu.co.uk/pug/GB/205N/5/51A02A.HTM

 

Item 3 and 4 

 

EDIT and 9A and 9B

Edited July 1, 2023 by PhilNW

[Gavin Waddell 18]

Yeah i adjusted it as described, the weird thing is the knock comes from the passenger side and not the drivers side where the shouldered adjustment stud is.

[welshpug 1,623]

put your original torsion bar in and try it, Bearings I doubt will cause this.

[Gavin Waddell 18]

They are the original torsion bars, ive only got a thicker ARB.

Thing is ive taken  the torion bar out 3 times now and it still knocks. 

[PhilNW 40]

4 hours ago, Gavin Waddell said:

However to make it knock i apply more of a lateral force than a rotational force.

Could not see the shocks in the videos so presume they were disconnected.

 

When the videos were done presumably the arm was in "full droop" equivalent to no load on the car and the knock occurs with more of a lateral force than rotational.

You get the knock when moving the suspension toward a loaded position (anticlockwise if LHS), do you get a knock when moving in the opposite direction from the droop position (Clockwise)

 

When driven the knocking occurs when the suspension is "fully loaded".

 

I can only think that there is some sideways/lateral movement of the trailing arm causing the knock but not quite sure what or where at the moment if the TB has been correctly fitted.

 

 

Edited July 1, 2023 by PhilNW

[Gavin Waddell 18]

Shocks were disconnected.

 

I havent tried to move the arm in the opposite direction, which is a good point.

 

When im driving it gets hard to hear at normal driving speed due to the the noise of the car, if i take it out of gear and coast and i can hear it.

 i doesnt happen when the suspension is under full load more when there are small bumps in the road kind of making the wheel chatter At the begining of the stroke. 

In the videos you can see that it make the knock with only slight movement .

 Like you said something has movment, as far as the torsion bar is concerned its held in place with the eccentric washer on one side and the stud on the other. Once you set the TA seal squish you back off the stud until it touches the end cap and lock of the nut? Thats how i did it.

 

[welshpug 1,623]

Sounds like the splines are worn in the trailing arm.

[Gavin Waddell 18]

Thing is it also knocks when the TB aren't installed.

[Gavin Waddell 18]

So quick recap.

 CAr has developed a knock on rear passenger side. 

 Knock happens when going over small bumps in the road and seems to be in the first 10-20mm of travel of the suspension.

When the car is stationary the  knock can be induced  when a lateral force is applied To the trailing arm.

( car stationary and shock disconnected)The knock can be induced when the trailing arm is not connected by the ARB/TB,

It also happens when the TB is connected but not the ARB.

When the the ARB and TB are connected it is harder to induce the knock. 

With all of the above innformation, it kind of rules out worn TB/ARB as the knock appens when they're not in place? 

 

Im going to start buy changing the bearings innner and outer and go from there. If the knock still occurs i will change the TA shaft.  

 

Any other ideas are welcome.

[PhilNW 40]

Hi Gavin

 

Re-read Haynes manual this AM, there is supposed to be a 0.002 inch gap between the arm and the suspension tube, can you check to see if there is any variation in the gap as you move the arm. The arm/TB should be held in lateral position by the fancy washer/arm and the threaded stud at the other end with just the gap for clearance.  

 

Did you try move the arm in the clockwise direction for any knocking?