405 Vibration...

[stevieb]

If it's the same as a BX (I know the Mi16 and BX are the same) you get access to it through the tower it's mounted in from the engine side and working from over the mudguard looking back towards yourself (if that makes sense) and you need an openended spanner to get onto it.


Alan S

Cheers Alan, but unfortunately it isn't quite that simple on mine. The tower is enclosed on all sides except for a couple of finger holes (and I mean one finger only). It seems to be tightened into a captive nut beneath/within the tower.

I only undid the top mount tonight (too cold and damp to try anything much more adventurous). I think on Saturday I'll remove the bolt from the bottom mount too, so the right hand end of the engine can drop properly, instead of rocking forwards towards the radiator. Maybe then I can get a chisel to it, and form a flat to get it turning.

In a new twist though - and after reading an old post on Aussie-frogs by you Alan - I decided to check the exhaust, and make sure that wasn't restricting movement, or seized at the front joint. Everything at the joint appearsd okay, but what I found was a fracture just forward of the joint immediately beneath the handbrake. The break is all down the right side of the pipe. Now I'm starting to believe even more that the engine is moving too much in its mounts. Admittedly the pipe is looking a bit rough, but the break isn't where you would normally expect it, near any joints/welds. I should point out that I uprated the bolts in my front mount some time ago, when I fitted this pipe, and compressed the springs more than usual to stop the pipe blowing at the front joint, so the joint is tighter than normal anyway.

Edit - The mount I have is like this one http://cgi.ebay.co.uk/PEUGEOT-205-306-3 ... dZViewItem

The bracket I have is NOT like this one http://cgi.ebay.co.uk/peugeot-405-alloy ... dZViewItem. The left hand (chassis) end of mine is completely straight, and shorter.

Sorry to use eBay pics, but couldn't find any others on net this quickly.

[alan s]

OK, I've just had a look at the Mi16 we have partially pulled down in the garage.
Support the engine by either a piece of timber sitting on a jack under it or preferrably an engine crane and remove the top mount. Now, whilst you may not think you have a mount like that, when you remove that bloody big block of cast iron or whatever it is sitting on top of the mount, you'll find hiding away in there that mount or something very similar. Once removed, it will reveal the engine mount like this:



The top thread passes through the alloy mount (as per the other photo) and once removed it will show it as you see above.
The bottom thread is held by a captive nut under the plate it is mounted on. If you look real closely at the bottom of the tapered part, there are 4 slots cut into what is a steel collar that runs around the circumference at that point. I would suggest that the proper service tool that would no doubt have a complicated part number would be something akin to a "G" spanner used to tighten cones on bearings near the pedal sprocket on a bicycle. As we won't have nor be able to get one of these, I'd suggest a steel or brass drift, sat in the cut out and given a smack with a hammer should loosen it and looking at the photo, I'd suggest it is a normal RH thread. Once you get it loosened it should just screw off by hand or at a pinch, a pair of multi grips may be needed. Might be an idea to give the thread a looking over before you start and if it looks a bit rusty (shouldn't but you never know) hit it with some WD40 and leave for an hour or so.
It should be easy peezy; might not look like it at present, but I think as soon as that top alloy plate comes off, you'll see what I mean.


Alan S

[stevieb]

Cheers again Alan.

The snag is the proximity of that end of the engine to the mount, and its height. The mount is basically enclosed on five of its six sides, with only the top exposed when the alloy bracket is removed.

Last night I removed the alloy bracket etc, and lowered the right hand side of the engine as far as it will go (with the lower mount still attached), to the point where it had rocked forwards and was resting against the radiator header tank.

Even at this point there isn't enough clearance to get a drift anywhere near the mount, let alone hit it with a hammer. The only angle of attck remains down. All the gaps that have been created by removal of the alloy bracket simply don't align with the target. I used a long flat-blade screwdriver to poke and prod for an angle of attack, but with no joy. The engine simply has to go lower... Of course, just lowering the RH side of the engine also tilts the top end towards the mount, which only serves to make matters worse.

I'll suss it out tomorrow, with a bit of brute force and swearing. I'll report back as usual.

Now I know why it took so long to get the head gasket done - they said they'd had to order a tool from France for it. And this was a main dealer...

[fastandfurryous]

Although a split engine mounting will greatly amplify vibrations, it's highly unlikely to be the cause of them.
The theory about worn driveshafts makes a fair bit of sense, and I would guess this is where the vibration is being generated, especially as it is only present under power.

Does your car have ABS? If not, then I have a pair of known-good non-ABS shafts you can fit to see if this is the problem.

I also have a fabricated tool for removing/refitting the upper engine mount, as shown above... very easy to make with a welder and grinder, and is probably the only way to properly fit a new mounting without damaging it.

Whereabouts are you based?

[stevieb]

Cheers F-and-F, I'm in Sheffield.

Things have changed again though...

I had a new front pipe fitted yesterday afternoon. The old one was cracked.

Afterwards I took an 80 mile round trip with a passenger - the same passenger I had when the vibration first started - and it's almost gone. Again.

There is no vibration at all when going dead ahead or turning to the left, even at high motorway speeds, with or without power.

Applying power and any amount of right hand lock sets the vibration going. Straightening up, or easing off the power gets rid of it.

Although I agree with you F-and-F about an engine mount not causing this amount of vibration, I've said before it feels like the triax rollers in a CV joint vibrating against the inner ends of their cups. If the engine/transmission unit is moving laterally, or twisting, it could be enough to over compress the driveshafts, or throw them out of balance. The split RH engine mount leaves the top of the rubber very weak, offering little sideways support. And something must stop the engine moving laterally within the engine bay, surely? The bottom mount doesn't, and the transmission mount can't, which only leaves the RH top mount.

The fact that the vibration changes every time anything to do with the mountings is changed seems to confirm this. The old front pipe might have seized in place and was holding the engine at this angle.

The other two mounts - when changed - have stopped the vibration until the rubber in them has stretched. Then it returns to normal.

I'll change the top mount anyway, and see what happens.

I expect to have to change the driveshafts anyway - they're either the cause, or they will have suffered damage from whatever the cause really is - so I'm going to have to buy a pair sometime soon anyway. Cheers for the offer F-and-F.

[stevieb]

Okay-doke. Apologies to Alan and fastandfurryous, the engine mount ISN'T that hard to get off.

In better light, and with the advice of you two, it came off quite easily - excepting the half-gallon of thread-lock used to hold it on.

I hadn't realised there really was metal just beneath the castellations, aS Alan had said. Every time I poked at them with a scredriver, they just felt like rubber, but sure enough, there is some metal just below.

An I managed to find an angle of attack with a long flat-bladed screwdriver. Without undoing the bottom mount.

Here is a pic of the mount in situ, after removal of the alloy bracket.



And here is one of the mount after removal. You can see where it has deformed.



In the top image you can see where the buffer rubber has rubbed against the paintwork. Notice just how much of the white paint is clean, which suggests to me that the engine has been doing a merry jig on the RH side at least.

I've taped in a small piece of thin wood over this area to take up the slack, now that the buffer is about 10mm higher (I was right about the rubber hex touching the bottom of the top plate with a new mount ), and obviously in a wider bit of the aperture. I've only shunted the car back and forth on the drive, but gear selection seems very positive. A proper test drive shortly when the roads are less manic will tell me whether I'm right or whether I'm going to get stuck in gear.

Again, I'll report back my findings.

[fastandfurryous]

I had a mount that looked like this on a 1.9D 405 a little while ago, and it didn't seem to cause to many problems, and certainly wasn't the source of low speed vibration.

The only problem it caused was after getting some fairly serious air over a hump-backed bridge, as I landed, the top of the mount (which is pointy-shaped) smacked through the rubber, peeling it open like a banana, and sat on the metal at the bottom. Cue some nasty high-frequency engine vibration (audible rather than anything else).
All this got was the engine jacked up, and several layers of rubber matting shoved into the space where the rubber once was. Worked wonders!

Thus, (as already noted, but worth mentioning again) I'm fairly sure that changing this mount will lessen the vibration, but it won't remove it alltogether.

Have you had a look at the long driveshaft intermediate bearing? if this is at all shot, the driveshaft and its fairly weighty inner joint can whip quite a bit, and would no doubt be the source of nasty low-frequency vibrations.

[alan s]

I'm glad you found out how easy it was. I read a couple of postings and was about to head out the door, camera in hand when I spotted your last post.
That mount looks pretty shagged to me. Be interesting to see what a new one brings.
Did a 700 klms run in the Xantia yesterday so have been trying to catch up on things today


Alan S

[stevieb]

Cheers, you two.

I've only had a quick run since sorting out the mount.

The vibration when riding crests in the road is gone - as far as I can tell so far.

The only vibration left is that when negotiating roundabouts. It's a strange oscillation kind of feel, almost as if one of the front wheels is wobbling from side to side. If anything, with the new mounts fitted it has allowed me to pinpoint the sensation even more.

It's definitely from the front left, but whether it's bearing or driveshaft, I'm not sure.

I see what you mean F-and-F about the intermediate bearing, and it was a little dry when I had the RH driveshaft off to change the lower mount, but there was no play in it at all. When I regreased it, it felt almost new, so I don't really suspect that to be the cause.

I'll be out tomorrow evening with my passenger/vibration-test-guinea-pig, so I'll have a better idea as to the problem. It's only very subtle when I'm in the car alone (I only weigh 10 stone), and obviously being braced by pedals and a steering wheel reduces the sensations a little more, so I'll get an impartial opinion on things too.

The new mounts have made gear changes nicer though, but I still get a bit of a kick through the stick, and there's a definite thunk when booting the accelerator pedal, which can now no longer be blamed on the mountings. So maybe there's some nasty slack somewhere. Maybe driveshafts, maybe within the gearbox... Who knows? Then again, it's still on the factory clutch, so maybe that's getting a bit tired after all those miles. Nearly 200,000 on the original clutch.

[stevieb]

Update time again.

With new RH mount now fitted, I only experienced the vibration when turning right and applying plenty of power (roundabouts etc) earlier today when on my own in the car.

I expected this to change when I gained a passenger (as said above). It didn't. Exactly the same symptoms. The vibration is MASSIVELY reduced compared to the last time I took the same route with the same passenger. So something is going right.

I'm still struggling to get across a good description of the vibration, so you know what it feel like. The closest I can do is to describe it as feeling like a 1/4" thick narrow strip of plate suddenly grows out of the left hand tyre, across its width. But it only happens when turning right, reasonably tightly, and only with power applied. It really is as if one tyre has suddenly become egg shaped. Except the tyres that are on are new since the problem started, so I know it's not tyres.

My suspicion is returning to the gearbox mount, and the fact that the lower end of the rubber is not actually touching - and therefore steadying - the gearbox end of the unit. I wonder if there should be an insert in the gap I have. This would explain why the problem seemd to start overnight, if it perished or rusted away and dropped out.

Rather than chop down the spacer and risk permanently making things worse, I'm going to cut up some old bike inner-tubes and pack out the gap to see what happens.

[stevieb]

UPDATE 2 - I've inspected my parts CD. For those of you with a copy of the CD, take a look at the engine mounts for the 405 td (405 since mod 1993/engine equipment/18A fixing power unit (last one on list). I have a gap between the bottom of the gearbox rubber mount (part 20), and part number 22. Is there meant to be a gap here? Does anybody know?

I reckon that a gap here allows the rubber mount to flex excessively, with nothing to stop the gearbox rocking back and forth (or sideways even).

[stevieb]

I thought I'd provide an update for those who were following this one.

Firstly, the vibration/shake/wobble is still there.

As I said before, the change of exhaust front pipe has reduced it enormously, but still I have this problem on right handers with application of power.

Wheel bearings have been checked and rechecked. The driveshafts seem square and true, with no discernible slop.

I still have quite a strong thump through the chassis when coming off the accelerator and then applying power again pretty quckly. There is no noise, but quite a strong thump, especially around 50-60mph, almost to the point where it feels like the engine is about to jump forwards out of the engine bay via the grille. With three brand new engine mounts I don't this should be happening.

Other than the shaking, the handling is unaffected, and I can corner at speed as usual.

The vibration/shake is not there when everything is cold. First thing in the morning it just isn't there (and believe me I've tried getting it to show). It's only when things have warmed up that the shakes get started.

With the thump I'm getting, I'm now looking at the small bush in the fork attaching the lower engine mount to the subframe. With the gearbox mount visible the other day, I blipped the throttle to see what area was moving the most, and it appears to be the bottom of the engine - still. The gearbox mount and top mount are only moving in "sympathy". The logic also suggests that the exhaust was had been holding the engine in a position it didn't want to be in, presumably exaggerating the problem, maybe overloading the mounts.

Replacement of all the other three mounts would also explain why the thump is more pronounced now, as the only mount/bush not replaced is this little blighter, which might just be struggling now the others aren't taking up any slack.

So that's one idea to try. Looks like a main dealer part though...

Another was suggested to me today by a former traffic cop. He suggested that it may be a strut showing signs of wear (slackness in its guides) - or being slightly bent. I suppose there is a strong argument, considering that the problem will suddenly surface when applying any amount of lock, but I've never had any amount of oil leak from either strut, and I guess I would've felt any slackness/looseness when I had the hubs off to do the balljoints. Anybody think this might be a possiblity? I know it's unlikely, but then the problem doesn't appear to be a "normal" one.

[Quinny]

Odd is that Steve,about it only being prominent when everything is warm.

I went from my house in Ossett,to Scunthorpe on Saturday night,and for about the first 5-10 minutes,my vibration wasn't as strong as normal.I had changed the n/s/f wheel earlier on in the day,and thought that it may be a tyre problem,however,once things had 'warmed up' a bit,my vibration was still there.

Now hopefully when you solve your problem,it may lead me to look at where mine may have a problem,and,because I'm new to Peugeots,will save me a lot of time and mucho headscratching.

Ken.

[stevieb]

I hope so mate.

I had a bit of a brainwave a short while ago whilst in the bath (as always when there's no pen or paper around to write them down in case you forget... ).

Anyway, when I exchanged the lower mount on mine, I made sure the fork was put back the same way round, so any problem this may have cause would only be repeated again. Now, if I get time tomorrow afternoon, I'll swap it round (If it's either split or gone soft on one side, then this'll work). It's only a two bolt out job, so it shouldn't take too long, then hopefully tomorrow evening I'll have my guinea-pig passenger, and I can see if the vibration has upped sticks and "moved" somewhere over to the right hand side.

If so, then I have my answer.

If not, then I can probably eliminate this mount/bush as being the culprit, and I'm back to looking at driveshafts/wheelbearings/struts/anything-else-that-might-just-cause-a-vibration.

I'll let you know when I've tried it out.

(Ideally I'll drop casually into a Pug dealer I just happen to be passing whilst out for work tomorrow, and they'll have one in stock - but I can't really see that happening, so this idea will have to suffice for now).

[stevieb]

I've swapped the fork round - but did it Thursday, not Wednesday as planned, so didn't get to do the "mate in passenger seat" test.

It seems to have reduced the thump I referred to earlier, but the "wobble" when cornering is still there. It might be slightly reduced, but the weather has been very cold here, and I've been taking it steadier - so maybe it's just my lower speeds which has reduced it.

One development has taken place though - When reversing off our drive (down a short ramp - 18 inches long, and about a 6 inch drop) I get a definite clonk from the front left. A lot like a knackered balljoint. Except the balljoints are almost new. It might just be an anti-roll bar droplink, but seems like it's worth further investigation. For a while now I've heard a groan from the front end when reversing off the drive, which I just put down to dry anti-roll bar bushes. Maybe it wasn't.

I know the car is understeering a lot more than normal at speed, so the anti-roll bar is something I need to check out.

"Come on taxman - let me have my money back - I need a new car... "