ARB bush clonk issue. Newish bushes

[bmbmdmb]

Over summer the front struts, ball joints, drop links, ARB bushes were replaced, including bolts and D bracket. No plastic collar on ARB bar, it's a 07 Vrs, late mk1 Fabia model.

 

There was a metallic tap noise over bumps. So I checked ARB bush visually and saw slight gap, see photo1.

 

I think I overtightened 13mm ARB bracket bolts. On a roundabout the front on car slide out and steering was stiff, let go of steering wheel and it centralised more quickly.

 

Torque is apparently 20nm, but impossible to get torque wrench on bolts due to drive shaft.

 

Anyway, I loosened off all 4 bolts to reduce compression on ARB bushes.

 

A few weeks later 300 miles or so, wife tellse there is a rattle. The ARB bar was loose on driver's side. I came out, tightened up at roadside, checked it when got home. 

 

Now the left side clunks when going over speed bump that is lower on left side than right and is steep speed bump. 

 

I read the bushes need to be tightened up with weight of car on them. 

 

Could it be that the bush is knackered? 

I don't want to loosen nearside only to have repeat of ARB being loose again.

 

I'm pretty sure it's the ARB btw.

 

ARB doesn't appear to have moved left or right when one side became loose.

 

Also consle bushes have replaced 25 k ago. They knocked when braking heavy , in turn.

 

Any suggestions? Replace with powerflex bushes?  Should I just take them out, have a look at condition? Everything on car OEM btw.

 

Thanks

 

[Breezy_Pete]

Those bolts are supposed to be 20Nm plus a 90° turn so you've massively under-tightened them probably.

I believe it is possible to get a torque wrench on them, you just need to adjust the height of the drive shaft by jacking under the outboard end of the wishbone to move the driveshaft out of the way, and use a suitable socket extension.

bolts are item 19 here: https://workshop-manuals.com/skoda/fabia-mk1/chassis/front_suspension_drive_shafts/repairing_front_axle/i_summary_of_components_assembly_carrier_console_axle_link_anti-roll_bar_coupling_rod_bracket_pendulum_support/

 

I would advise replacing all four bolts with new before re-torqueing them to the spec. as they will have been fatiguing in their movable/undertightened state since you loosened them, and they are supposed to be replaced whenever removed anyway.

 

 

Edited 18 January, 2019 by Wino

[bmbmdmb]

Thanks Wino,

 

I'll buy new bolts. 

 

 

 

 

[KenONeill]

@bmbmdmb  Given the angle-tightening after torqueing, get a suitable spanner and measure its length in metres. Convert this length to a vulgar fraction (eg a 0.333m spanner becomes 1/3). Get a spring scale calibrated in kg. Using the scale to pull on the spanner, tighten until the scale reads 2kg divided by fraction, in this case we have 2 div 1/3 for 6kg on the scale.

 

@Wino - I wouldn't suggest this if the torque wasn't part 1 of 2 of tightening the bolt up.

[LightRain]

@KenONeill That's belt and braces, I like it

[rum4mo]

Sometimes not so easy to carry out in real world conditions, though I do have a couple of springs balances that have been used for that and steering arm articulation setting in the dark past.

 

If you really like to make life easier, there is always the Laser Tools 7286 Torque Adaptors, though I'd suggest to rethink the method they give for working out the de-rated or altered torque value - I have space in my tool storage unit for a set of them, though justifying the price does look tricky.

 

OP, when you replaced these ARB mounting bushes, you did buy the correct ones for ARBs without the plastic sleeving - though I thought that VRS never ever had plastic sleeving on it ARBs, I could be wrong there.

[bmbmdmb]

7 hours ago, rum4mo said:

Sometimes not so easy to carry out in real world conditions, though I do have a couple of springs balances that have been used for that and steering arm articulation setting in the dark past.

 

If you really like to make life easier, there is always the Laser Tools 7286 Torque Adaptors, though I'd suggest to rethink the method they give for working out the de-rated or altered torque value - I have space in my tool storage unit for a set of them, though justifying the price does look tricky.

 

OP, when you replaced these ARB mounting bushes, you did buy the correct ones for ARBs without the plastic sleeving - though I thought that VRS never ever had plastic sleeving on it ARBs, I could be wrong there.

Yes, went to dealer for all parts. 

I torqued with car on jack's, then read later that I should have tightened up fully with car unsupported.

No plastic on ARB bushes, they were like for like , all rubber and same shape, size. I suspect one of the bolts has bent slightly when the other side went really loose and despite tightening up they have slight play only noticeable when going over speed bumps a little too fast. 

I ordered fresh bolts and have a go next weekend.

 

 

I do have an old analogue weighing scale I don't use...thanks Ken.

 

Laser tools sounds good Rum, being a tool junkie myself. Just bought more tools for repair of leaking kettle to gain access to tamper proof screws. Tri wing etc.

 

[LightRain]

14 minutes ago, bmbmdmb said:

Laser tools sounds good Rum, being a tool junkie myself. Just bought more tools for repair of leaking kettle to gain access to tamper proof screws. Tri wing etc. 

 

Sorry for butting in, but just a FYI. If you do go for torque wrench extensions, make sure you use the right calculations to account for them. Wikipedia has the correct ones (at the moment at least ), many sources don't. You probably know what to do, but I'd hate someone to mess up due to poor information.

[bmbmdmb]

9 hours ago, LightRain said:

You probably know what to do, but I'd hate someone to mess up due to poor information

Thanks. I found the equation

M1 = M2 x L1 / L2

for adding extension to torque wrench that would increase torque over what is actually read by torque wrench. Could not find conversion table on wiki.

 

I can get to one of the 2 13mm m8 60mm ARB bolts with a ratchet wrench . I have a Halfords  small size torque wrench for that.

 

If I'm honest I think I reused a bolt on passenger side of car which has issue now, due to access issues with driveshaft. On driver's side I had to remove driveshaft nut to get suspension strut out, new one in, so both bolts were replaced.

 

  

 

 

[bmbmdmb]

I think Wino's idea is easiest.

 

 

Thanks

22 hours ago, Wino said:

jacking under the outboard end of the wishbone to move the driveshaft out of the way, and use a suitable socket extension.

 

Just to check when car is supported on other jack's plus stands I can compress spring to get more access jacking near ball joint on wishbone, but not on ball joint or its bracket?

Edited 19 January, 2019 by bmbmdmb

[Breezy_Pete]

Yup.

[rum4mo]

I'd tend to jack right out at the end as a bonus the lower swivel retaining bolts act to grip any wooden packing that you are using.

 

You seem to be a bit bothered by torqueing the ARB mounting bracket bolts while the car's wheels are off the ground, for my money that is not a problem as the ARB does rotate within these mounting bushes - it is only in situations where you have a bonded bushing, that it is essential for maximum service life to carry out the final tightening with the vehicle down on its wheels or the wheels supported so that the suspension links are at their natural positions/angles - as these bonded mounting do not allow any rotation, just temporarily flexing.

 

My comments about the plastic sleeve were aimed at the original ARB if VRS/GT/Cupra early models ever did have plastic sleeving which attempted to retain the sideways movement limiting washers - no ARB mounting bushes had plastic sleeving.

[Breezy_Pete]

Yeah sorry, replied without reading very carefully. Jacking under balljoint is probably better than on wishbone itself, but it won't take much force to move things enough. 

As for torqueing with bushes loaded, can't see it making the slightest difference.

[rum4mo]

10 hours ago, LightRain said:

 

Sorry for butting in, but just a FYI. If you do go for torque wrench extensions, make sure you use the right calculations to account for them. Wikipedia has the correct ones (at the moment at least ), many sources don't. You probably know what to do, but I'd hate someone to mess up due to poor information.

 

Unless it got it completely wrong, the method outlined by Laser Tools for "de-rating" when using torque adaptors is wrong, which surprises and saddens me, I can see their outlined method working if you were using one of these torque wrenches that had a long pointer and a deflection scale at the operator's end of the handle, but nowhere else.

[fabdavrav]

I just packed out a thick wodge of paper & wooden offcut under the ball joint & jacked the wishbone up.....bolts have to be done up as per spec otherwise things loosen & fall of!!

[bmbmdmb]

Thanks all. I'll report back when completed next weekend.

 

[bmbmdmb]

There is a reason I didn't change the front left wheel ARB top bolt...

Just no way that bolt is gonna go in there without taking driveshaft out from inner CV joint. 

I'm not sure it's the bolt that's fatigued. I'll replace bottom one for now which is accessible. 

 

On this side of car, jacking wishbone up will make no difference as inner CV joint is so close to the bolt.

 

If only the bolts screwed in from other side, although steering gaiter is obstructing lower bolt then.

[sepulchrave]

It's not the bolts but the brackets which fail, this is why Febi ARB bush kits come with new brackets.

[bmbmdmb]

It's sorted now.

I used new brackets when I replaced ARB over summer. I have today replaced just one bolt on the problem side, loosening both bolts and on the other ARB as I had  problem getting the new bolt to bite on  the bracket. Did all bolts up on each side in turns to gradually seat bracket and not distort  bolts. They are quite long.

 

Test drive, no issues. Knocking has disappeared. 

 

 

 

[bmbmdmb]

On 26/01/2019 at 15:41, sepulchrave said:

not the bolts but the brackets which fail

Not entirely fixed this. This morning when front left of car stooped down mining related subsidence there was the knock. It's alot better than before. 

Sepulchave - do you think it's worth changing bracket on left side of car and even bush. I could probably live with it but it might only get worse. The right side was the side that was loose and rattling about. Could it damage ARB bush  on opposite side, left side of car? There febi kit for £10 er and another 1 or 2 hours joy messing with spanners. 

Anyone else had this happen?

[bmbmdmb]

Could the rubber ARB bush be damaged and need replacing after such a short time?

Worth putting powerflex ARB bushes on. Less likely to flex?

What size powerflex. 18mm I ve heard rumoured?

[Breezy_Pete]

Check that you haven't got a broken-away heatshield knocking onto the exhaust/body anywhere. People have changed all sorts of things only to find this was the cause of the clonk/clunk.

[bmbmdmb]

Yes, I had a good look around and push pull, rock , etc. It all started with the ARB being loose then tightened.

[bmbmdmb]

I'm buying new ARB bushes. Old ones state they are 19mm but looks like ones on car now are 18mm they supplied. They suggested they could be 19mm due to variation in model. So have supplied wrong size. Darkside have said I have 19mm and have 20mm ARB . 

Have a look at photo with 19. Is it reasonable to expect 19 is 19mm?

That part number has now been superceded if any one if using it as s guide Btw.

Thanks

[Breezy_Pete]

As far as I can see here, the available sizes of rubber bush are described as 16, 17, or 18mm  (item 11): https://skoda.7zap.com/en/cz/fabia/fab/2005-453/4/407-407010/#11

If you look at the ARB part numbers, item 10, it tells you which bush suits which in the 'note' column, as well as the PR codes matching up in the 'data model' column.

 

The biggest, with N suffix seems to have been superseded by suffix-R, is that what you've seen too? Other two don't appear to have been superseded.

 

Edited 1 February, 2019 by Wino