405 Mi16 - Acceleration Wobbles

[pips]

I went out for a long drive today.

Down to Cronulla for some fish and chips. Then the plan was to drive over the Old Princess Hwy down to Bulli Pass.

I got the fairly new roundabout where you can turn off to go to Stanwell Tops. Waited for the cars to clear so I could continue. All of a sudden, upon acceleration, I get major wobbles through the entire car. I can feel it though the gear lever, the steering wheel. And visually see the front of the car wobbling.

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I am unsure of what this could be. It only does it on acceleration. It does it in every gear. 1st gear is the worst, 2nd not as bad, 3rd alittle less, and so on till 5th gear. Where it can just be felt.

Would this be the drive shafts? Diff? Gear box? CV? I turned a corner both left and right handers at full lock at slow speed to see if there were any noises. There are no noises at all. Although, now there is a thump after changing gear and hitting the accelerator, making me think engine mounts.

I've also noticed alot of low down power has gone. And when I stopped on the side of the road to check out the wobble. ie: Missing wheel balance weights, lost wheel studs. I pulled some stones stuck in the tread out, thinking that could be adding to the problem of the wobble. But yeah, power has gone as well.

I will be jacking the car up on a hoist tomorrow to have a better look. But in the meantime, any direction would be appreciated.

What I don't get is, how and why on earth would something like this happen? It's not one of those things that is caused by wear and tear. I would logically assume that it would be caused by hard driving. Which I was not doing. What would cause this?

Thanks,
pips

[Stuey]

pips, I think you'll find there's an engine misfire problem that has just happened to reveal a possible engine mount problem. There's a voided rubber mount at the lower rear of the block which really commonly fails and which curbs fore and aft movement of the engine - it could be this one. I've just replaced mine, and it involves removing the RHS driveshaft as the shaft intermediate bearing is mounted in the casting that holds the engine mount. A pretty easy job, though, and the mount is only $25.

Good luck

Stuey

[pips]

You are saying this in relation to the car losing power afterwards? Or the wobbles?

So, you are saying it could just be the lower engine mount? Which when looking at the Haynes Manual. If you happen to have one, is located on page 1.7, titled "Maintenance & Servicing". There is the underview of the Mi16. Part number 11 is the Rear Engine mounting, located near the intermediate bearing housing.

I hope this is just it. Replacing drive shafts sounds more expensive.

The thud sound happens during acceleration. Stomp on the throttle, THUD, acceleration.

Also, one thing I forgot to mention earlier was that when I did stop the car to check out the wheels, etc. When i got back in to start it, it kept cranking over but not firing up. I sat there for a few minutes and tried again. Same thing. After 10 mins, I tried again, and it slowly started to sound like it was getting fuel and about to start. it did, but like it was starving. eventually it did.

Thanks
pips

[Stuey]

Only the wobbles...but...if there's an audible thud, it's probably not the rear lower mount, as when this goes there's still rubber to rubber contact because the rubber just shears, but the engine and gearbox moves around more. Weird that a thud just starts, which is why I thought the misfire (or whatever) has just revealed an issue with a mount, suspension, exhaust hitting firewall, etc.

Regarding the running issue - I wonder if the fuel filter is blocked? It's down the back above the rear suspension, a steel canister type.

Stuey

[pips]

Yeah, the wobbles only occur while accelerating. The thud happens if I jerk on the throttle. Similar sound to the dash when you do over a large pot hole. But its definately in the engine bay area and I can do it each time I slam on the gas.

I didn't really notice any misfire. I did notice that the engine sounded like it was idling really low after that though, for a while. Then it didn't start at all, but it was okay on the way home, bar the wobbles on acceleration.

I still can't get over how its happened so suddenly, and without a noise, or warning.

What side of the rear is the filter? Left or right?

pips

EDIT: I drove the car this morning while there was no traffic on the roads. I am starting to have contractive thoughts. I accelerate and throttle off (engine braking) and on acceleration, can see and feel the car wobbling. Off the throttle (engine braking) I can feel the gear lever moving in sync with the wobbles. When cruising on the throttle, ie: not accelerating or deccelerating, there is no wobble at all, the gear lever doesn't move.

So, from this... If it were drive shafts, wouldn't it do this wobble regardless of speed, acceleration, braking as it is a constant rotating mass?

Also, this tells me its more to do with the above metioned lower engine mount at the base of the block, that stops engine/gearbox left and right movements.

I will be going to my brother-in-laws workshop this afternoon (or maybe this morning if I feel like it) to see what is the G O.

pips

[Haakon]

This may sound silly, but check your ignition leads (if its a series 1). I had a lead come adrift from the dizzy cap on the R25 that did just that - made the car wobble as the motor fired on 3 pots under power. But with the lead sort of still in position, enough "spark" was able to jump the gap and allow it to idle OK. If its a series 2 car, you may have coil pack failure (I hear they get cracks that lead to weak spark on a cylinder)

Could also be a spark plug failure - these give the same symptoms, or a blocked injector/dodgy injector plug connector.

Just pull all the plugs - the colour will tell you which cylinder is misfiring.

[pips]

I checked out the plugs. All are okay, all are the same colour and all are fairly clean.

I also checked the resistance of the ignition leads, HT Coil etc. and all are within spec. Nothing out of the ordinary.

I did notice when I got under the car that the lower engine mount rubber looks like its perished. I can see through the circular mount in some places.

I have spoken to that guy in Lugarno and gone to see him. He is flat out for the next two weeks. But gave me some tips, and confirmed that its the engine mounts. Top bloke who does know his stuff. He was so helpful and polite, he even told me that sometimes his work can cost more then the dealers depending on what problems he finds along the way to fix. Plus taking into account that he does not have the support of a large spare parts department. So for some jobs it might be worth while to go to a dealer instead.

I'll see what happens when the parts arrive and I replace the lower engine mount.

Thanks
pips

[matt205]

Certainly sounds like engine mounts to me, BUT could also be control arm bushes, my 205 had a nasty case of the wanders due to this, new bushes solved it.

Also it's worth checking the top engine and gearbox mounts too, a failure of the lower mount puts a lot more stress on the others, failure of all 3 while driving will probably lead to driveshafts coming out of the gearbox or cv joints coming apart or both, I've seen this happen on another 89 MI-16. Given the cost of the mounts and the relative ease in which they can be replaced it may be worth doing all of them.

[pips]

The car doesn't wander all over the road. and when I steer, its very tight, as it should be.

The wobbles only occur on the throttle where its more of a shimy rather then a shake, and I don't lose control of the car. it still drives straight.

Visual inspection of each mount has shown that the bottom engine mount is the culprit. the others are still good.

I know what you mean by replacing all of them, but I am strapped for cash at the moment but I can do them as well, in a few weeks time. Until then, just the bottom one will be replaced. Its the biggest bitch of the three to do as this one requires the removal of the drive shaft.

Something I have never done on a car before.

I wonder if any one of you are willing to come over and give us a hand? There's Crownies in it for ya!

Either way, it's gotta be fixed by this weekend. Parts are on their way up from Melb. This place is good, half the price including express postage of any Sydney dealer or auto shop.

Thanks
pips

[Stuey]

.Either way, it's gotta be fixed by this weekend. Parts are on their way up from Melb. This place is good, half the price including express postage of any Sydney dealer or auto shop.

I assume you mean Caravelle?

pips, the standard lower mount does have holes in it - that's what I meant by a voided mount. This allows progressive fore and aft movement (which I think translates to 'rocking' torque reaction of the motor/transmission) being stiffer the greater the movement. I've seen 'motorsport' mounts that are solid rubber, but I guess these would transmit a fair bit of buzz to the body.

Consequently, if you do it yourself, make sure the holes are in the same spot. The solid bits of rubber are vertically aligned when mounted. You can use a hacksaw to carefully saw through the outer metal ring of the mount from inside the mount until it can be collapsed in. However, you'll need a press to get the new one in.

One consolation is that your gearshift will be more positive with this mount fixed.

Cheers

Stuey

[pips]

A hole is one thing, but rubber bits hanging around, looking like its all rotten, ripped and shredded. That's another thing.

I was told that I will need a 20 Tonne press to remove it. I'll probably give it a shot of penetrating oil before hand.

I was also told to rub the new rubber with copper grease of some kind, which I happen to have, still in my tool box from when I use to use it on sparkplug threads. I was told that I would not need the same pressure to put the new rubber in the housing.

I didn't get a good look at the thing today, to determine what it looks like exactly. So you are saying that the rubber bushing has a slot in it to allow for movement? That makes sense if it does, but this was definately missing rubber from what I saw.

I didn't get to get it up on the hoist today. My brother-in-laws work shop was flat out today so I didn't want to disrupt him. The parts will arrive tomorrow and I'll machine the front discs at the same time.

I was reading throught the manual and see that the drive shaft has to come out anyway. As I said, I didn't get a good look under the car today, but looking at the dismal workshop manual pics. It looks like the drive shaft inner CV joint/bearing housing is actually part of the mountand its all bolted to the block. Am I right in picturing this?

Am I right in saying that the drive shafts are relatively easy to remove? I read in the w/s manual that its a matter of undoing the main, centre bolt in the hub, turning the front wheels to one side.

pips

[Graelin]

Thanks for sall the advice my brother in Perth has a 405 SRi with exactly the same problem. I drove it and you can feel the wobble come up through the seat.

I have passed on this info.

Thanks

Graelin

[pips]

Edit (16:18):

Hey all, I received the parts today.

Went to fit them but was greated with yet more problems. I found that the right hand diff seal is leaking like crazy.

I also discovered that the gearbox mount (left hand engine mount) is worse then the bottom one.

So I cut my loses and decided I'll just machine the discs, only to discover that they are well out of spec with regards to their minimum thickness.

Very productive day.



pips

[pips]

Why oh why does the drive shaft have to go through the bottom engine mount?

This job has become a disaster. The more things I open up, the more worms I see in the can.

Would it be sensible to say that the transmission side engine mount would be easier to get at if I remove the battery and its tray?

pips

[Stuey]

pips, you can use a press to remove the old mount from the housing, but an easier way is to take the blade off of a hacksaw, pass it through the holes in the rubber in the mount, and re-connect it to the hacksaw frame. Then saw into the outer steel shell until you just get through the steel. Use WD40 on the blade to stop the rubber binding it.

Use a cold chisel to tap the edges in where it's cut, and the steel will collapse slightly, then you can remove the old mount. Remember to mark the alignment of the solid rubber bits of the mount - I used the hacksaw blade to mark a nick in the aluminium.

I did use copper grease on the steel surround to re-mount the new one, but don't put it on the rubber!

Yep, you remove the centre hub nut (35mm). Follow Haynes, but one point is that the two 11mm (?) nuts on the bolts that go through the engine mount housing to hold the intermediate bearing (just inside the inner CV) need to be backed off until they're about 8mm from the end of the bolt, before you can push them in and rotate them so that their eccentric heads will release the bearing.

The mount housing is held onto the block by 5 (or 6?) bolts and is located by two dowels onto the block. Sorry, I should've mentioned that you should replace the diff seal as a matter of course - they are as cheap as anything and VERY easy to replace.

Everything else is as per Mr Haynes. Note that the torque of the hub nut is 194 lb/ft so it needs a fair old lever.

Cheers

Stuey

[pips]

Thanks Stuey

How easy will it be to get the new rubber bushing back into the mounting housing? I have copper grease ready. I was thinking of leaving the bushing in the freezer for an hour and leaving the mount outside in the sun.

I've never removed a drive shaft before. Not on a car anyway...on a bike. BMW's, etc.

I have no idea. I can't see how the shaft moves. Undo the centre bolt, (34mm? I know 32 is too small and 36 is too big, could be 35mm)EDIT: DUH, I just re-read your post, Its late, I'm tired, and hungry, 35mm socket. Then what? Do I pull on the shaft? The guy in Lugarno said that I will need to give it a good pull because there is a circlip that expands inside the dif housing, it sits around the splined bits that go into the diff housing.

I've order the remaining engine mounts as well as the diff seals and also a fuel filter. I'll have to contact a dealer here for the fuel sender unit, or a wrecker.

I think this is the biggest job I will be doing on a car, ever. Surprisingly, it feels daunting, as I have been off the tools for years and that was when I was rebuilding bike engines in a days work.

Thanks for the advice. I was getting alittle worried earlier today. The thread not getting responses like I've grown use to on this forum. Just me, bitching and moaning.

mate.

We shall see how we go.

pips

[Stuey]

Howdy again pips,

The outer end of the shaft has to come out of the hub first. See page 8.2 of Haynes - paras 4-7 and then 10 onwards. You need to loosen the nut on the lower balljoint and separate the joint. Remove the anti-roll bar bolt to the suspension arm. Then remove the lower ball joint nut completely. It's a bit of arsing around, but you have to then lever the suspension arm down to get the lower ball joint taper free, because you have to swing the hub out a bit to get the driveshaft free of the hub.

Then get under the car to release the centre bearing - see para 10? That's where I meant that you have to loosen the nuts until they're 8mm or so from the end. See pics 2.10a and 2.10b - the latter is the picture of the housing after the bearing's been removed - see the tabs turned downwards?

When the nuts are this loose, you can push the bolts in until the nuts are against the aluminium mount, and turn them so the tabs holding the bearing aren't in the way. (These are 'L' shaped on the end of the bolt and swing onto the bearing outer track to hold it in place.)

Back out at the hub, turn the hub as per Haynes and pull the shaft out of the hub. This is probably the hardest part. Once it's out, you can wire the shaft to the suspension somewhere and go under to release the shaft from the diff - very easy to pull out by hand. Then go to the hub end again, and supporting the whole shaft carefully feed it out of the suspension gubbins. Done.

The mount housing can how be unbolted...

Oh, Haynes doesn't say this, but I recommend removing the steering arm balljoint too, for better maneuverability of the hub.

Stuey

[pips]

Stuey,

Thanks for that info. I should be receiving the remaining parts today.

Man, some of these Pug dealers in Sydney are slack. I've called up some places for fuel sender units and they've either said, "Sorry, can't help you, the cars too old" or "I'll call you back in half an hour" .... I'm still waiting 3 days later.

Anyway, these guys in Melb can't get the sender unit, so I'll have to look at wreckers. Which I found, most are still closed till around the 18th or so.

pips

[David Shearer]

Stuey,

Thanks for that info. I should be receiving the remaining parts today.

Man, some of these Pug dealers in Sydney are slack. I've called up some places for fuel sender units and they've either said, "Sorry, can't help you, the cars too old" or "I'll call you back in half an hour" .... I'm still waiting 3 days later.

Anyway, these guys in Melb can't get the sender unit, so I'll have to look at wreckers. Which I found, most are still closed till around the 18th or so.

pips

Hi pips,

how much are sender units worth?

cheers
Dave

[pips]

I have no idea.

Dealers I call can't give me the price right on the spot, or the availability. I get told to give them the model and year. Then get told that they will call me back in 30 mins. That's service! I called one of them back earlier today, and he didn't even remember me. Then proceded to ask for the year and model and said he will call me back in 30 mins.

Must have been a recording.

And yeah, I can't call wreckers, cause ones that I did call are all on holidays.

pips

[Stuey]

Could be worse, pips. The Pug dealer over here wanted the VIN every time I rang, so last time I called with the VIN and they wanted the 12 digit part number...off of a torn, greasy driveshaft boot that was still on the car...

Needless to say I went to Caravelle.

If you have no joy, I know this mob in NSW have some Mi16's and will send by mail:

Reno Reck (02) 4353 1618

Cheers

Stuey

[matt205]

I get my genuine bits from Mildren's in Sydney, speak to Steve James, he's a very enthusiastic Pug owner (206 180) and knows older Pugs like the MI-16 very well. Steve normally looks after trade parts only but if you mention your are from AF I'm sure he'll help you out.

[pips]

Cool.

What do you mean by helping in other ways? Mechanically?

I just found out that my access to a workshop will be unavailable for two weeks.

This means that I won't have access to a hydrolic press or a hoist to make life easier.

Anyone live local to Padstow that has a hyrolic press and could let me use it? The guy in Lugarno (he might) didn't offer to let me use his, I didn't ask, but I might when my parts arrive on Monday.

Thanks for the info guys, and all the tips. We'll see how we go on Monday. I just hope its just the engine mounts.

pips

[Jack Z]

Pip,

At the end of the day it's a fifteen year old $4,500.00 car... surely it is not unreasonable to expect some wear on key components.....

I know it can be daunting and disheartening when these things apear and mutiply particularly when you so diligently scour every avialable one prior to purchase in the belief you have found the best available....

I couldnt begint to imagine what a VN comodore or EA falcon would like like under the same scurtiny....

Once sorted however you will have the joy of an engaging drive, in something safe, sporty, and comfortable... and the frustration will fade...

Until something else breaks!

[pips]

Well,

At the end of the day, I am fully aware that it is a 15 year old car. But I've driven older cars with worse condition and engine mounts aren't one of the things I expect to be fine one day, and just let go you on the next. Considering they are rubber, the material tends to slowly shift away from its original form, visually, physically and chemically.

I expect things to go wrong, hence why I bargain, then that leaves a margin for me to spend the left over money on fixing any issues that arrise.

I can imagine and see old Falcons and Commos all the time because my Brother-in-law runs a workshop and has quite a few customers with these cars, including taxis.

I don't think I have once said that I thought it was unreasonable that the car needs fixing. What my concern was, was the design of the rear engine mount. Having to share the same lump of alloy with intermediate bearing housing for the right hand driveshaft. Something like this could have been easily designed around. But its a pure sign of cost cutting. No manufacturer says, "hmmm, lets design this so that Joe Blow can fix it himself in the shed."

That's fair enough, but at the same time, still a pain in the arse to have to fix.

I am well aware that I will be enjoying the car once its all fixed up. Truth is, I was thoroughly enjoying it right up till the excessive wobble started.

Sorry if you have interpreted my thread in that way. I have always been annoyed with other engineering things. Which is why I hate Honda motorcycles and some of their cars too. But admitedly love their reliability (bar their Regulator/Rectifiers - Those things are shockers). Saying that, I don't hate them as cars, I hate them as jobs. The fact that you must take so many things apart to get to one simple thing that could have been better thought out.

Anyway,

I was still thinking about the left side engine mount. Is this accessable from under the battery? I ws just looking at it from under the car and its tight in there. Maybe the battery and the tray can be removed to allow for easier access?

Hope so.

pips