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Top hat loose on my MK Indy!, check them guys
sonic - 28/5/16 at 06:37 PM

I jacked my car up to day to take the wheels off and clean them, near side front top hat on the top wishbone popped out!

put it back it and the bolt felt tight but wasn't nipping it tight enough, long extension bar and its tight now. I then went round every nut and bolt I could find to check, luckily no more loose one found.

Check them guys it could have been fatal if it had come out at speed.


daniel mason - 28/5/16 at 06:44 PM

I keep checking the top and bottom upright bolts on the Jedi. The lower front seems to work its way loose regularly


ian locostzx9rc2 - 28/5/16 at 07:09 PM

I know of few people have drilled an extra hole to put another bolt in them .


sonic - 28/5/16 at 07:29 PM

I was just thinking why can't I drill straight through the middle of the casting and tophat, but a bolt straight through.

it cannot come out them, or will it weaken the casting?


ian locostzx9rc2 - 28/5/16 at 07:32 PM

As per last post that's what a lot of people have done


CosKev3 - 28/5/16 at 07:33 PM

As above,you should really drill through and fit a bolt as a secondary securing point.

IIRC someone did say some IVA testers check for a secondary fitting,as on a Sierra as standard there was no way the strut could come out of the hub even if the bolt came loose.

I recently had mine come loose,I think yours will again as the cast hub does not clamp onto them tight enough.

I welded some seams down the mushroom then with the hub spread open with a chisel I ground back the welds until the mushroom was a nice tight fit into the hub,then once I pulled the chisel out the mushroom was already held in pretty tight.
Then once the bolt was tightened up its much better


sonic - 28/5/16 at 07:42 PM

I think I am going to drill straight through the middle of mine tomorrow and fit a bolt through, it cannot go anywhere then.

More I think about it the more I think it could have been fatal if that had popped out while giving it some beans over a hump on the road.

Thanks


CosKev3 - 28/5/16 at 08:09 PM

I had a bolt with nylock on mine and it still came loose,the bolt won't hold it tight,it's just a fitting incase the main bolt comes loose


Irony - 28/5/16 at 09:39 PM

Mine came came out on a early road test. Odd to see the wheel flopping about about. I was doing less than 10mph at the time.

Secondary fixing is a requirement for IVA


Toprivetguns - 29/5/16 at 06:41 AM

Drill and tap - insert bolt a with loctite.


Bluemoon - 29/5/16 at 07:09 AM

Not had an issue with mine; but a secondary locking mechanism is a good idea. Mine were tight even with the pinch-bolt undone.. Fresh Nyloc's plus tell tail white paint and correct torque setting is all I have at the moment.

Note: with the McPherson strut there is a lot of shock loading on this part and the whole weight of the car... in the Indy only sideways loading from cornering loads.

Dan


SJ - 29/5/16 at 07:52 AM

quote:

Not had an issue with mine; but a secondary locking mechanism is a good idea. Mine were tight even with the pinch-bolt undone.



+1

Another job on the list!

I got mine MOTd on Friday though so back on the road now!

I'll apologise in advance for any negative effect this has on the weather.


hazardpro - 24/9/16 at 08:59 PM

could someone please post a pic of the area please (kit car newbe alert)!


CosKev3 - 24/9/16 at 09:20 PM

If you have Sierra front uprights it's the piece fitted into the big hole at the top of the upright where the macpherson strut went in on the Sierra.

Your top balljoint is mounted into the 'mushroom'


CosKev3 - 24/9/16 at 09:25 PM

Description
Description


In that pic it's the round silver part in the Sierra front upright at top of pic


hazardpro - 24/9/16 at 10:13 PM

thanks guys


flanders - 3/10/16 at 09:41 AM

anyone got a picture of the secondary bolt fitted?


CosKev3 - 3/10/16 at 10:29 AM

quote:
Originally posted by flanders
anyone got a picture of the secondary bolt fitted?


You just drill straight through upright and mushroom then use a bolt with a nylock

Will take a pic of mine next time I'm in garage


coozer - 3/10/16 at 10:55 AM

I had to drill and bolt for the SVA back in the day...

Drilled a 7mm hole, tapped it m8 and put a nyloc on the back for added security.


flanders - 3/10/16 at 12:55 PM

cheer lads!


flanders - 23/2/17 at 10:34 AM

Kev any chance of that picture? ive got my suspension fully stripped off at the moment so its an ideal time to add the bolt. Iv got an idea in my head of how its done but i want to be 100%

on a side note, the ball joint mounting hole in the mushroom is offset, can i take advantage of this and introduce more castor angle?


CosKev3 - 23/2/17 at 11:50 AM

Yeah will try and remember.........

Ref castor I'm no expert,but have read on here that the mushroom can't alter it.


flanders - 23/2/17 at 12:18 PM

Thank so I've been waiting patiently

Ah ok. So any idea why the top hat has the offset hole? Camber perhaps?


Matth93 - 23/2/17 at 04:19 PM

The hole that the ball joint bolts into on the mushroom should be as far forward as you can get it (so leaning the top of the hub backwards) to give you some castor although on my car it doesn't give enough to get self centering on the steering


Camber Dave - 23/2/17 at 05:33 PM

Rotating a mushroom with an offset ball joint will not change the CASTOR
This is arranged by the set back of the upper and lower ball joints.
Rotating the mushroom moves the hub not the position of the ball joint.

It will enable you to fine tune the CAMBER

But remember it will affect the BUMP STEER by raising or lowering the steering arm.


Matth93 - 23/2/17 at 06:35 PM

I have just copied this from the MK build manual.

Changing the camber you should only screw the top ball joint in/out of the wishbone and keep the mushroom in the SAME location each time. The mushroom is there to adjust castor and should normally be set such that the top of the ball joint is as far forward as possible.


Camber Dave - 23/2/17 at 07:11 PM

quote:
Originally posted by Matth93
The hole that the ball joint bolts into on the mushroom should be as far forward as you can get it (so leaning the top of the hub backwards) to give you some castor although on my car it doesn't give enough to get self centering on the steering


It is quite correct to arrange the most offset between the wheel centre and the hubs's axis of rotation does give some castor.

However unless the upper ball joint is 3 to 5 degrees behind the lower one insufficient caster will result.

I had this problem on a Dax Rush about 10 years ago. The Dax manual also quoted the same as the MK
However the castor gauge showed the truth. New top arms fixed it and gave the owner stability and confidence.


SJ - 24/2/17 at 07:57 AM

IIRC The mushroom doesn't change castor as moving it doesn't change the position of the top ball joint in relation to the bottom. Castor angle is the variation from vertical of a straight line drawn through the centre of the top and bottom joints.

I modified my top wishbones by putting rose joints on instead of poly bushes to allow the wishbone and therefore top ball joint to be moved backwards.

This does make the steering much better and increases feel, though even with around 7.5 degrees of castor self centring is still fairly weak on the Indy.

Not sure why - several people have said this is is due to chassis flex which could be right. Personally I think there are probably also other geometry issues in play but not sure what. The car self centres great when going backwards!

Either way the rose joint mod is a fairly easy and cheap mod to do and improves the steering feel a lot.

Stu


MikeRJ - 24/2/17 at 01:23 PM

quote:
Originally posted by SJ
IIRC The mushroom doesn't change castor as moving it doesn't change the position of the top ball joint in relation to the bottom. Castor angle is the variation from vertical of a straight line drawn through the centre of the top and bottom joints.



Correct, it does not change the castor angle as this is fixed by the ball joint centres. However it does allow a small change in trail (distance between tyre contact patch and steering axis centre) by effectively moving the wheel back or forward, and trail also helps with self-centring.


SteveWallace - 24/2/17 at 05:01 PM

quote:
Originally posted by flanders
anyone got a picture of the secondary bolt fitted?


This is mine just pre-IVA. The silver looking round thing just below the mushroom is the allen key headed bolt that I used.


[img] Description
Description
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flanders - 24/2/17 at 05:51 PM

Ah ok I get it! So just drill right through the. Upright and the mushroom, the I take it there a locknut on the other end of the bolt inside the upright?


SteveWallace - 24/2/17 at 08:51 PM

That's right. There's a nyloc on the other end of the bolt. A bit fiddly to get on but it went through IVA without comment.