[trackday_prep] 405 Mi16 Track Car

[petert 588]

If you drove it like you stole it, it wouldn't make any difference. ie either 0% or 100% throttle. At zero % on overrun the fuel would be cut off anyway, and at 100% the mixtures would be correct.

[JeffR 51]

I did the repair to the injector bungs on the weekend and glued them in with a few dollops of JB Weld.

Also found the throttle bodies out of sync and the rubber seal for the 2 halves of the airbox perished & leaking. All fixed in readiness for Sandown next Sat.

Last time I was there I put my keys and sunnies in the recess where the radio used to locate only to have them fall onto the floor under my feet on the first lap so picked up an elasticised pocket & mounted it to the door trim.

[JeffR 51]

Had a great day at Sandown today other than fairly severe brake vibrations.
The set up is 406 coupe Brembo calipers and 305mm discs on to 405 hubs.
Since the calipers are hard mounted to the hubs with no sliders, should I be considering a 2 piece 'floating' brake/disc/rotor assembly and would this eliminate the vibrations?

Thanks

[welshpug 1,661]

shouldn't need to do that to stop the vibration, its a standard factory arrangement, albeit on a 405 shell not 406.

 

what pads? probably just left some deposits on the disc, or there's play in a balljoint.

[JeffR 51]

Balljoints are a possibility as there was little to no pulsing of the brake pedal-mostly through the steering wheel. DS3000 pads.

[wicked 103 3 Cars]

Warped discs maybe?

[welshpug 1,661]

not likely, dont think Ive ever seen a warped disc, if pedal feels good then I would certainly look at balljoints, lower and TRE could well have been cooked by brake heat.

[JeffR 51]

Achieved another 1st in class (1500-1999cc) at Sandown so that's 2 first places & a second in the championship so far. The standings will be published next week.

 

http://www.msca.net.au

[speaksgeek 5]

Well done. Mine's still on blocks waiting to be finished... I'd love to be challenging you for that podium.

 

Achieved another 1st in class (1500-1999cc) at Sandown so that's 2 first places & a second in the championship so far. The standings will be published next week.

 

http://www.msca.net.au

[JeffR 51]

I'll skip the Rnd 5 Rob Roy Hillclimb event and wait for Rnd 6 again at Sandown June 18.
Any chance you'll have the 180 ready by then? Need to show that the French can do fast too!

[speaksgeek 5]

Not likely unfortunately. It's off to get wiring in June, then some testing, hopefully ready for some summer fun.

[JeffR 51]

MSCA are pretty slow at updating their results page so here are the standings after Rnd 4-

 

 

 

[petert 588]

Nice work. Don't miss any more rounds!

[JeffR 51]

Still dogged with brake vibrations. Couldn't find anything that looked suss. Balljoints and tre seemed OK. Can't think of anything in the rack that could cause it. I'll go through it all again before the next round at Winton.
Anyway, despite the braking issues I still came away with a class win and maintaining the lead in the Championship.

[wicked 103 3 Cars]

Warped discs maybe?

 

Did you try other discs? I had it once... It doesn't have to be much to make it vibrate. Off the brake you won't notice, because it is floating indeed, but during braking it is not really floating anymore.

 

Edit: if you don't have other discs at hand, you can have them skimmed. It can also be done while mounted: http://skimmydiscs.co.uk/

Edited June 20, 2017 by wicked

[speaksgeek 5]

Have you got a dial gauge to have a go at measuring the runout of the disc/bell? If not, happy to lend you one.

[JeffR 51]

Have you got a dial gauge to have a go at measuring the runout of the disc/bell? If not, happy to lend you one.

Yes, part of my cam timing kit. Thanks for the offer though.

[JeffR 51]

I checked for disc runout today and one side has 0.003", the other 0.004". I'm yet to remove them and check for any runout with the hubs.

I had this vibration through the steering wheel (not the pedal) problem with the original Brembo discs so replaced them with the current Valeo ones. Pads are DS3000.

TBH, they probably didn't get the proper bedding in procedure being a track only car.

This makes for an interesting read...

http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths

[calvinhorse 870]

Great video and result

 

Could it be a flat spot on a tyre?

[JeffR 51]

Could it be a flat spot on a tyre?

If it was tyre related the vibration would be felt at a particular speed/s when driving. This only happens while braking.

[JeffR 51]

I missed the last round at Winton and dropped to P2 in the series still chasing the braking vibration.

Last time I had this issue I fitted new Sasic ball joints which solved the problem. They did have some play in them so swapped to German Meyle this time.

Hopefully problem solved.

A bigger issue has developed with one of the Gaz Golds shocks. The 405 uses a clamp arrangement holding the lower leg of the shock to the hub. The crush on the shocker has split the welds where the tube bottom is welded in and now leaks.
Took it to the local Gaz agent for repair but all he could suggest is using an epoxy (like Belzona) over the end. I would have preferred to dismantle the unit and have it re-welded. I'll still have the issue of replacing the lost oil.

It's not practical to send it back to Gaz in the UK for repair before the next round.

Has anyone dismantled a Gold before or have a schematic of one?

No pics thanks to Photobucket.

Edited July 31, 2017 by JeffR

[B1ack_Mi16 67]

Are they a bit poor quality in general or have they worked good apart from this?

 

I have a set from the group buy for my 405 T16, but don't think I'll be fitting them, mainly due to MOT reasons and that they're not legal to use over here without TüV papers though.

But it seem really poor if they manage to crack in the welding there.

[JeffR 51]

Also got mine through a group buy here. Until now, I've never had a problem. I torqued it up to the Haynes specs-41lbs ft (55Nm) where previously just spanner tight.

 

My concern in using an epoxy is that it might crack under compression when fitted.

[welshpug 1,661]

any damper service tech should be able to fix it for you, is it an inverted unit with a nut on the bottom though?

 

if it is then you can strip the insert out yourself.

[JeffR 51]

any damper service tech should be able to fix it for you, is it an inverted unit with a nut on the bottom though?

 

if it is then you can strip the insert out yourself.

No unfortunately, access to the innards through the top of the tube.

 

I'll take it around to the local Koni agent.