DNF at FFO Sunday scenic drive

[Charley]

I heard a nasty rattle coming from the right rear of my Beta Coupe about half way through the Sunday scenic drive at Fiat Freak Out.I stopped along the road to investigate.I first thought maybe the RR wheel was coming loose.Nope...wasn't the wheel,all the bolts were tight so I pulled back the carpet cover around the strut tower and found the strut mount had broken,the rubber just let loose.BIG BUMMER ! :'( I limped 35 miles home at 30mph. Luckily,no other damage was found after a closer examination.
Here (http://lancisti.net/photopost/showgallery.php?cat=897) is some photos of the broken mount,The thing that scares me is the rubber "looks" fine :confused: ,no apparent dry rot.I guess the mount rubber simply had a weak spot,or was just brittle from heat and age.

[Will]

It must have been that ionizer- very very bad for rubber parts! :)

Seriously, try cleaning both sides with acetone, wipe with a slightly damp rag and smear with polyurethane glue (Gorilla Snot, Elmer's Ultimate, etc). May sound crazy, but that polyurethane glue sticks to rubber like you would not believe. It'll probably be stronger than original after you glue it.

My.02

[davidb]

Ges Louize glue for something that critical ? I say no. NOS or salvage.
A '75 - '78 Coupe rear mounting plate is: 8235861. The rubber bumper
is: 82351970. Obert ? DiFatta ? Salvage ?

[davidb]

Sorry, the plate part # is: 82358861. Don't ever get old guys. I
had to get out my magnifying glass to read the fine print in my
old Mitchell manual when I suspected I missed a digit. YIKES !

[Charley]

Hey thanks for the replies guys.I already looked into new mounts at all the usual vendors,with no luck.The mount that broke was actually used.I picked up two of them on ebay last year and they were from Arizona if I remember correctly.I had the whole suspension apart last winter and the original mounts were a bit rusty,so I put on the nice pretty desert set (paint still on the metal) I shelved the RUSTY originals.So I will sandblast the rust off the originals and paint them.I should have done that in the first place but I got lazy when I could just install the "Pretty" ones.I guess the trade off was the rubber was brittle from 30 years out in the desert somewhere,nice paint though.

[DJ]

Yep.

After having bought a Scorpion and a Zagato from Arizona my standard procedure is to replace ALL rubber on a car from the desert. If you don't, you're just asking for trouble.

[davidb]

Charley: Tried Di-Fatta? Regular vendor they're not but they come up
w/some squirrely NOS stuff. Obert of course too {OUCH}! Agreeing
w/D.J. about desert cars & perished rubber won't help you a wit. You
have the part #s. Hopefully that will give you a leg up for searching.
Even salvage would be better than glueing. That's not a good idea.
Mine opinion but there it is.

[Will]

Ges Louize glue for something that critical ? I say no. NOS or salvage.

Well, all I can say is PUR adhesive is good enough for GM to stick Corvettes trogether with and I read recently that virually ALL of the Tatas are bonded with PUR. With a shear rated 500-1500PSI up to 2K+ for 2-part PUR, it's likely adequate IMO. The strut tops have literally NO continuous loading, it is all transient loads and things like tire pressure and road surface can play big roles.

I have blown out Scorpion strut tops but they are different- in that case, the strut pokes through a hole in the flimsy steel strut top, driving the strut up against the bottom of the trunk or engine lid. A check strap is not a bad idea for these if you haven't rewelded your strut tops (I welded thick fender washers on mine)

"Salvage" is great if you can find them except many times because of the age of these cars, what you get is worse than what you had. Early on, I bought a bunch of parts from Bayless that were worse than what I was trying to replace, so I just don't anymore. I dropped the $168 for a gallon of Forsch polymer urethane and will recast (higher durometer) parts as necessary. After msking s mold for ther supercharger bracket out of the Forsch poly, I learned that it is tough as hell and sticks to everything.

[davidb]

I knew you'd "chime-in" Will. Salvage pts. are of an unknown value/quality
agreed. I said/implied NOS, . . . THEN salvage! I stand by my opinion that
adhering, glueing, any nature of adhesive, is inadviseable for a suspension
part this essential to handling & safety.

[DJ]

I certainly wouldn't disagree that some of the modern adhesives are simply amazing.

However, I'd still be reluctant to do this with a strut top because I would assume that the rest of the rubber is just as bad/weak as the rubber where it broke. I would worry that all you may be doing is gluing bad rubber back to bad rubber and it would likely tear away again in a different spot.

Just my 0.02.

[Will]

I certainly wouldn't disagree that some of the modern adhesives are simply amazing.

However, I'd still be reluctant to do this with a strut top because I would assume that the rest of the rubber is just as bad/weak as the rubber where it broke. I would worry that all you may be doing is gluing bad rubber back to bad rubber and it would likely tear away again in a different spot.

Just my 0.02.

That's an excellent point- DJ. I did look at Charley's pictures and note that his issue is really that the metal cone debonded from the rubber- except for a small bit of rubber on it the thing appears to be an issue with adhesion of the rubber to metal. He states that the rubber appears fine, which is the only reason I suggested gluing it.

He could certainly try gluing it and then pressing the bushing back out to see if it's stronger/weaker than the other ones he says he has on the shelf and that should clear up any speculation.

I wouldn't suggest anyone glue rotten rubber mounts back together, but unless parts like these are remanufactured or reimported, scarcity will eventually dictate that we repair them. This is only possible if the old ones are saved, or at least the metal cores. I managed to give away a lot of old usable-core stuff I didn't want to keep but the cultural attitude of "junk it, buy another" may get us in trouble one day when a needed component simply cannot be found.

I'm very fortunate in that respect in that I have the tooling to make or adapt other options, but I realize a lot of folks are rather limited in this area and the rapidly disappearing local machinists and job shops don't want anything to do with our old budget Italian contraptions.

So save those cores! :)

[Charley]

Hmmm...I opened up a can of worms now.I value all of your opinions and comments.But I have decided to simply clean up the original mounts and install them,UNLESS I can come across a pair of NOS somewhere.David,I met Chris Obert at FFO,he was actually on the Sunday drive (up in the front of the pack somewhere). He told me he would be parting out a 78 Coupe soon FYO, in case someone needs something from that car. I haven't tried DiFatta yet...I was thinking about Will's "Gorilla Glue" option,and I would agree with him that the repair would likely be stronger than hell,...but then as DJ said there could be a failure elsewhere. Interesting delema. As for the correct part number for the mounts, that is a whole different can of worms !! I looked on my broken "Desert" mount and found 82358859 stamped in the rubber,which matches the number I have in a Mitchell Manual for a 1979 HPE.The original mount (that I am now cleaning up) has 82313539 stamped on it,which the Mitchell lists for a 1975-1978 HPE. The Mitchell manual has 82313430 listed as the mount for a 1975-1978 Coupe. The number David gave me,82358861 is listed in the Mitchell as fitting a 1979 Coupe.. Now how's that for confusion?? I guess they would all fit my 75 Coupe ?!

[davidb]

If you have a Mitchell manual then good. Part #s I gave you should be
for a Coupe, '75 - '78 Coupe. Yes it lists HPE on the same page. Not sure
but I would think the HPEs would be different 'cause they took different
struts than a Coupe. IIRC HPEs & Sedans shared suspensions: struts, etc.
giving the "ass-up" look. X-reference the HPE #s to Sedans. If they're
the same then fitting a Coupe is unlikely. Mitchell should have listed HPE
suspension bits on the Sedan page & vice-versa rather than on the Coupe
page. That woulda cinched their being different, i.e. not for a Coupe.

[Will]

You know, I don't even think the rubber part is the root of the problem with Charley's strut. I'm not familiar with that exaxct strut, but Charley, take a look and see if the shoulder on the strut shaft ate its way through the top of the "tower" part and punched thru.

In that case, you need to make up a flat bushing or washer that goes over the top of the strut shoulder to keep the strut from punching through in bump (compression).

The rubber can then be glued just fine because the angle of that cup suggests that it was designed to resist rebound loading only. A pic down from the top of the assembly, or further disassebly of the unit would help here.

I have NEVER been able to figure out FIAT's wacky parts numbering, but the things that determine a strut top are going to be size and PCD of fasteners, size of tower, size of strut shaft and strut shaft shoulder, and height of strut shaft shoulder relaltive to strut tower top. (did I miss anything?)The latter is not real critical and the cars having different struts may be a major thing or as subtle as different sized holes in the compression valve disc, which you could never tell the difference by eye even if you took the struts apart!

I have only two types of strut here (Zag and Scorp) and the shaft diameter is the same, and the shoulder diameter is the same (the nuts are different, but tha't minor).
My point is that even thouigh there are different part numbers, the strut tops may be virtually identical or easily adaptable.

If you don't want to investigate the failure mode of your strut top Charley, I'll be glad to pay the shipping on it if you are going to ditch it because I'm curious as to what happened to it and howe it's constructed. If it's the hole in the top of the tower part we may have identified a weak part that I 've known for a long time affects the Scorpion model but perhaps the Coupes or Zagatos as well.

I did not even think of this before since I was loking at the failure of the rubber. It just occured to me that there should be more metal on the other side of the rubber, if this strut design follows that of other models.

[Jim Keller]

Make sure you check the strut it's self, maybe it was the problem and broke the upper mount. I have seen them jambed and just paid an extra $140 on a Koni rebuild due to internal damage from being bottomed out and bending the shaft as well as demolishing the valve, causing it to bind.


So far as glue?, todays modern chemicals are remarkable at the least! I LOVE today's glues and epoxies! LOL as the old saying goes: "Better Buzzes......er.....Living Thru Modern Chemicals" LOL

I would be willing to bet, we gould all gather a bunch of upper rear strut mounts, as well as front ones, from a Zag, Coupe and HPE and find no differences to speak of from all years. Maybe even Sedan may have same style upper mounts, donno, but the only difference in the HPE over Coupe and Zag "as I understand from what I have been told only", is the rear strut travel and spring rating, most likely only to compensate for the extra weight the HPE is rated for in the rear, so I doubt they made a different upper mount just for that, I am realitively sure the mounts would interchange

[Charley]

Will,I like your idea of adding a large washer to the top of the strut rod.The end of the strut rod had pushed through the top of the mount with the cone attached and prodtruding over the tower.When I jacked up the car the cone retreated back into the hole in the mount. I didn't even have to install the spring compressors to remove the unit from the car.The strut stayed together,and I installed the spring compressors at the bench as usual.
Jim,The strut seems good.I compressed it to the bottom numerous times by hand,and it compressed smoothly with no binding,then the rod returned smoothly to full extention by itself. Every thing there seems good. I guess I simply had a bad mount.Or another possiblity is I may have weakened the bond between the cone and rubber when I ran the nut on with my impact wrench.
Again,thanks to all for your input !

PS,I added a few more pics (http://lancisti.net/photopost/showgallery.php?cat=897) of the broken mount and some of the replacement mount that I'm cleaning up to install.

[1,6 HF]

...Or another possiblity is I may have weakened the bond between the cone and rubber when I ran the nut on with my impact wrench...

Charley,
I'd say that's a very real possibility. I'd seriously consider tightening the replacement with a torque wrench to the factory setting (no, of course I don't know what that would be..) rather than an impact wrench.

[Will]

Charley,
I'd say that's a very real possibility. I'd seriously consider tightening the replacement with a torque wrench to the factory setting (no, of course I don't know what that would be..) rather than an impact wrench.

Yeah, that cone should have slots in it like other applications do, the bonding to the rubber isn't the best solution IMO.

BUT - I'd put money on Charley's problem being metal fatigue of the strut top hole, and the whole rubber issue being a mere result.

I don't know a lot about Coupes, but I can tell you for sure that on the Scorpion, once you start changing the bump valving (or putting more viscous fluid in as the guys do that don't have the ability to change the bump valving) then the top will try to punch through on the first series of sharp potholes you run over. You really NEED to reinforce the strut top mounts before you do anything performance-wise to the struts, and it would be a good idea even for stock struts, IMO. UInless you live in a place where there are no potholes, which unfortunately neither Charley nor I do. I can see this being an issue for the Coupe as well, if the part is under-engineered as much as the Scorpion part.

[Charley]

I think I may have another problem to deal with besides a broken strut mount.I was in the process of adding some large washers to the end of the struts (as Will suggested),and after removing both struts from the car I found that the right strut was extremely stiff when pushing in on the rod,and the strut would immediately extend to the full extension when released.The left side strut was much softer and has to be pulled upon to return to the full extension,dampening in both directions smoothly.I believe this is what caused the right strut mount to break. I believe the valving in the "stiff" right strut must be damaged.Comparing the dampening action on the struts side by side has lead me to believe this.The struts are KYB Excel G inserts that I installed back in April of 07. Any thoughts about why a relatively new strut failed so quickly ? Now my problem is sourcing new replacement inserts.One of the guys from the UK's Beta Boyz club helped me before with these KYB inserts .
https://sslrelay.com/buypartsby.co.uk/kyb-shock-absorbers-rear-details.php?recordID=1077
It seems none of our vendors has inserts or full units available.I guess I will have to buy another set of the KYB'S,and hope this doesn't happen again. Any input is appreciated.

[Will]

I think I may have another problem to deal with besides a broken strut mount.I was in the process of adding some large washers to the end of the struts (as Will suggested),and after removing both struts from the car I found that the right strut was extremely stiff when pushing in on the rod,and the strut would immediately extend to the full extension when released.The left side strut was much softer and has to be pulled upon to return to the full extension,dampening in both directions smoothly.I believe this is what caused the right strut mount to break. I believe the valving in the "stiff" right strut must be damaged.Comparing the dampening action on the struts side by side has lead me to believe this.The struts are KYB Excel G inserts that I installed back in April of 07. Any thoughts about why a relatively new strut failed so quickly ? Now my problem is sourcing new replacement inserts.One of the guys from the UK's Beta Boyz club helped me before with these KYB inserts .
https://sslrelay.com/buypartsby.co.uk/kyb-shock-absorbers-rear-details.php?recordID=1077
It seems none of our vendors has inserts or full units available.I guess I will have to buy another set of the KYB'S,and hope this doesn't happen again. Any input is appreciated.

I'm not very familiar with the KYB inserts Charley, I do know that the ones you have use a multi stage foot (bump) valve and Kayaba like most vendors will cover struts under warranty UNLESS the insert was too long for the application or you lowered the car, both of which can allow the piston to come down and mash the compression valve. If you can't get it covered under warranty perhaps you could do a postmortem on the strut because I'd like to see it, what went wrong. Good luck.