Last night I got to installing new UMI Upper strut mounts and new Monroe Sensatrac struts.
Problem: The struts won't fit into the mount's bearing. I tried lightly chamfering one of the struts, thinking it might be a press-fit, and was able to get enough of the strut-stud through to put the nut on. I tightened it up, an once I released the jack holding the control arm up, the strut pulled the bearing out of the mount!

What gives?

 

Do you have pictures you can share?

Reason I am asking is because your description does not make sense to me-why?- because you state the strut "pulled" the bearing out of the mount when the strut should push up from underneath- maybe just an incorrect choice of words on your part? just verifying this first.

 

Now assuming you ment "pushed", the strut you are using very possibly has a larger top stud then the strut mount bearing opening...??? This is something UMI will have to address as long as the strut is the proper Monroe replacement strut for these cars- maybe you are using something someone sold you and said it would fit when maybe the strut you are using is not really intended for this application? who know, this is why I ask to get to the real problem.

The car seems to me that it is lowered a bit also because the lesser distance of a strut length distance of a lowered car would push the bearing right up and out if the strut is fully compressed and the stud is against the bearing with the full weight of the chassis on it. It most likely pushed the retaining clip right out breaking it and forced the bearing up and out. For what ever reason, sounds to me like the strut stud and the bearing I.D. (inside diameter) are not compatible in size.

Dean

 

Here are some pictures after I took it off. Like you said, the strut piston/stud is too large to fit in the UMI bearing. The UMI bearing has some sort of bushing inside of it, and you can see where it came out.

Picture #1 is how the strut came out when I released the jack.
Picture #2 is the spherical bearing, AFTER I HAD TO PRESS IT OFF OF THE STRUT. Luckily my strut wasn't damaged. (Monroe p/n 71728E) Note the bushing sticking out.
Picture #3 is the housing, without the bearing.

 

I am puzzled when you say "released the jack" but I see the pictures clearly and see what is wrong. So lets start with the jack part- Was the jack under the car lifting it making the distance of the strut position longer (wheel dropped out from the fenderwell) and when you dropped the jack the strut compressed as the wheel touched the ground and the car came down- thus pushing the strut harder on the underneath side of the strutmount? This would be a normal sequence...

...yet, as I asked before you said the strut pulled the bearing out of the strutmount when you released the jack...and, I see in the picture #1 that the strut munt bearing is perfectly seated and the strut nut is tightened onto it, yet it is not in the strut mount obviously. Did this all pull out the bottom of the strutmount somehow? - because it would not pull through it properly installed and the jack was released- it would push in, not pull out.

I could be mistaken, but for some reason it looks like picture #3 that the strut mount is not even in the car. Were you trying to press this together or something outside the car?

 

The snap ring wasn't properly seated into the lower portion of the strut mount. This allowed the bearing to drop down out of the mount. Assembly error on their part.

Look into the mount where the bearing goes, note the groove at the lower end. That is where the snap ring seats.

In the 1st photo you can see the snap ring between the shock and the bearing (the gold piece). Push the bearing back into the mount and seat the snap ring into the groove. The snap ring is damaged so should use a new one.

RBob.

 

I have a stock strut here at my desk (for answering this question). It measures 0.671-0.672 where the bushing rides. We press a sleeve with 0.675 finished bore size into the 3/4" bearing. This allows the stock strut, and most other struts, to fit properly in the hole.



The shaft itself on the factory strut is 0.990" OD nominal and is large enough to seat on the face of the inner ball and prevent the sleeve from pushing out through the top.

The snap ring prevents the bearing assembly from coming out the bottom.

 

You are not going to like me for saying this- but are you serious?

I have never had one of your units in my hands to see this and had no idea you are making them in this manor. That is about as dangerous as it comes. You are seriously reliying on a snapring to hold a major suspension point in place in the car? That piece should be machined for the bearing to be inserted ONLY from the top and held in by a snap ring- thus if the snapring were to ever fail- and I had one fail on my HMS unit due to aluminum fatigue- then the strut shaft still stays located inside the strut with a little wobble, yet does not come completely detacted falling out underneath.

A very poor and dangerous design. I am amazed you have not had a failure. One of these snap rings comes apart on the freeway and that assembly works it way out the bottom and you can kiss someones *** goodbye...wow.

 

I would have to agree in this case. I can't believe it is designed this way. With this method the bearing can't possibly be retained tightly in the housing, not to mention the obvious snap ring failure point.

Now I'm going to have to pull one of my J&M mounts and see how they do it. I suspect the same as all these companies copy each other. If so, I guess I have another project on my hands.

 

Thread the ID of the tube up to the snap ring. Thread another tube on the OD. Place your bearing in there and screw it together,

Then use set screws to make sure the tube does not come undone. You could use grub screws but I think they are unnecessary.

With all that said a properly installed snap ring is not a problem.

20+ years as a millwright dealing with things under way more load than any of our cars will ever dream about.

 

Wow this is not good. I have those same strut mounts.

 

The issue really isn't the strength. The snap ring is on the low load side and a snap ring in that size will have a max allowable thrust load in the neighborhood of 5000lbs.

My big issue is the fitment. It seems like the design requires there to be some slop of the bearing in the housing. It is not firmly locked in place.

 

Exactly my point, it is bad enough with one snapring on the top side that I have eventually had fail- hence why i state the prototype strut mounts I was part of the first prototype group I am the only person i know to have had issues with it. I strongly recommended Steve Spohn manufaturer his the same way but out of steel. I also asked it if was possible with production cast to do so sort of threaded bearing retainer somewhat like rawley is saying, but more along the lines of how Spohn did the Delspere joints. THis way any play if it develops can be taken out of the bearing insert so as not to pusle against in housing and snap ring in dynamic motion.

Having two rings is just potential for twice the slop as fatigue sets in since the retainer ring is not that thick. Then by al means having one on the bottom where something can come out- and you made my exact point- it someone does not have it seated correctly- we are called humans for a reason, we are not perfect. That is a catastophe waiting to happen- and almost already did from the OP above.

Im sorry Umi, i would not run one of those- and if I found out I had one on my car I would drive it home very scared and slow and get it the heck off there. I am not bashing against anyone, I am speaking from the heart on how safe or unsafe I would feel about that part on a car I had to drive.

What the heck I do in cars? my life is worth more than a little snap ring can provide safety wise. That thing could fail and work its way out of there if you do not have gas charged struts and merely driving down the freeway at 70mph- there goes your steering

 

I had billet 6061 housings that had a snap ring insert groove 1/4" deep into the channel and the 6061 fatigued and thus the snapring sloped and failed.

There you go.

But this was on the top side. The strut just topper out against the bottom of the housing underneath so no harm no foul. I shimmed it and put another new snapring into it. it worked like that for another few months and I was about ready to order steel units when life took a little change and I no longer have the car to worry about.

had that failed from underneath? I can think of all the major stress moments I put on it that would have killed me had it let loose then. if it happens, it will happen to me, I swear. I even had a regulator plug on me scuba diving 40feet under water and had to bail out to the surface 3 years ago- you never know so I like to take the risk out as best possible. (On that note- I dove for over 25 years, but will not ever again until I get certified so I can buy and service my own gear- like packing your own parachute.)

 

You don't have to worry about ours. We machine our cups to be a press fit with the bearing along with using a sleeve retaining compound as added security. We also don't use c-clips but we use spiral lock rings. They always say copies are never as good as the originals

 

Should have been doing some maintenance.... I would never think snap ring on top would be safe in any sense of the word. That is the LOAD SIDE.

I must have missed the part about the bearings being loose in the housing. I thought I read he pressed it out. I may have misread it.

 

[Foghorn Leghorn] "Fortunately, I always keep a spare, for just such an occasion."

 

Could just be my monitor but I can tell at all from your pics? Dont have a close up of the top.

How are they holding the bearing in?

 

I thought we were talking about the bottom?.......Here are some pictures from the top.

 

So it looks like there is a lip on the sleeve that the bearing is pressed up against. The press fit holds the bearing but the lip acts as a secondary protection for the bearing popping out the top of the sleeve. I can't tell from the pictures, but it sounds like from hotpart that there is a spiral lock ring that is the secondary (after the press fit) insurance that the bearing doesn't pop out of the bottom of the mount. That is a robust design if you ask me.

It also gives you an audible alert of an issue as if the press fit fails, unlikely, you will likely hear the bearing rattle against the lock ring.

Well done.

 

Both sides are the load side, with the bottom having much more load than the top side due to higher rebound damper settings. Compression damper is generally always less resistance then rebound damper settings. Why? Because the compression side is weighted mostly by the coilspring plus light dampering, the rebound siude has to slow and control the recoil of the coilspring so the bottom side takes much more load than the top side.

This is exactly why Machinist should not engineer car parts. They should refer to a chassis dynamics expert.

Regardless of load, the safety factor should ALWAYS render the bearing not ever being able to come out of the bottom so as not to loose one of three MAJOR front suspenion connection points.

 

I would not say originals, yet you are first to have separate caster adjustment which I must say I have adjusted several of your sets many times doing track alignments for local guys and then back to street setups afterwards. Yours are in fact very easy to work with.

HMS (Hunter Motorsports) were the original soild bearing strut mounts back in about 2001 if I recall. Karl did a prototype run for about 20 of us. I know two people personally that still are running theirs today witht he original bearings in place and absolutely no problenms with fatigue on the 6061 aluminum. I was the only guy to waste my bearings in mine in 3 weeks. I replaced them with identical OD and height pspecs, but a bearing that was 3 times as expensive (the best axial load rating bearing money could by- I can dig up the archieves and find out what bearing I ran if you are interested) but after that I had no bearing issuesfor the next aprox 4 years. The continual pounding I gave this car and the high damper rates I ran, the mount itself finally fatigues and the clip broke up top. I shimmed it and glued another new bearing in place (Nothing wrong with the 4 year old one- but figured if I was going to now use glue on it I wil use a new bearing and then next time I will have to toss it for new steel units) I ran that for several months until I no longer had the vehicle.

Hunter dropped any further production run of these- then Steve Spohn came out with the exact same design as it was tried and true, yet with the apporpriate steel units rather than aluminum. Steves work great to this day and I really trust his design with the cup machined from the top so as to next allow the bearing to ever slip through even press fit. It hits against the bottom metal.

Hotparts- I thought yours was the same but with the separtate caster adjustment feature- I actually have been recommending you design as I am sure you remember my "Ultimate handling threads". Something to say about your lifetime gaurantee Two thumbs up. I did not know your bearings were press fit and glued also- I just know if they ever wore out you have listed the gaurantee. We have them on Valentins car and they are going strong. These are so much easier to dial in then the Spohn ones even though I think Steves design is very safe and solid also.

Dean

 

Machinist is a pretty small part of my job. A real small part. I know from reading your other post its pointless to debate you. But to this

I will say this. Your top snap ring did not fail in one day. It took days or weeks to fail. That was on top. I still have not read one post from anyone saying the bottom one did. Yours was a prototype and the bottom snap rings are in full production so its safe to say there are more of them.

I am going to disagree with you on the bottom taking more of a load than the top and leave it there. If you have something besides your word. Like some kind of actual research I will be more than happy to read it. I will admit I do not know everything and I like to learn.

I will say IF the bottom is the load side I would be worried about the 4 bolts holding the bearing housing to the strut mount more than the snap ring. They look like 1/4-20 bolts to me in what looks like 1/4 inch plate. Could all come apart. That is less than 5 threads on each bolt. More like 4 threads for a total of 16 threads holding it together. Not good at all IF the bottom is the load side.

I don't worry about the bolts because I don't think the bottom is the load side. The top is not under much load also judging by the way the factory mounted them.

My guess is the worst loads are during corners when its trying to push from side to side.

I am not trying to be a smart *** I am actually rebuilding my stock suspension and plan on replacing my strut mounts. Thats what brought me to this thread. I am trying to learn.

 

Wow, I just ordered a set. I mean literally. I completed the order and then came here to find this. I called summit and and cancelled my order. So what brand should i use?

 

That's the million dollar question.

I would love to see the founders ones. I was planing on ordering them.

 

Crap...I have a brand new UMI set sitting on the shelf ready to get installed next week.

 

Are your bearings pressed in or are they sloppy?

 

I just explained to you the bottom was more the load side and explained to you why.

I also said it took 4 years until it failed. There are FAR MORE top snap ring units put into prodduction. UMI's units are fairly new.

If you feel comfortable with two slivers of 3/32 metal snap rings holding together your front wheel assemblies from coming apart underneath you as you drive your car- they hey, go buy them if you trust that.

If anyone doesnt think the bottom is the load side? then ask yourself why is the strut mount assembly mounted in the top side of the strut tower? Try shimming a stock unit off the deck of the strut tower and watch it bend over time- there is a photo archieve on here of some who did that trying to gain strut body clearance on a lowered car- the force of rebound damper eventually bent the stock strut mount housing downward in between the 3 bolt pattern.

A lot of people do not understand the dynamics of chassis and suspension motion forces.

 

I think the clear choice at this point is the J&M.

 

The bearings are a tight fit to begin with, They are machined very tight tolerances where alot like a wheel bearing race, they will not fall out, but can be easily tapped out.

The problem with the snap ring is after millions of cycling force is applied to the snap ring going down the road as the sturt dampers bumps and dip in the road (yes uts cycling all the time) the pressure on the snapring edge starts to fatigue and the snap ring eventually starts to develop a click noise just like rodends do.

 

Slicktrackgod, Could you give me some reassurance on why the 4 small bolts on the Hotparts/J&M are sufficient?

 

Perhaps a PM would be best.

I would answer you questions, but I'm not slicktrackgod.

 

It's actually been addressed in another thread... the four small bolts are quality hardware on par with the three small studs and nuts holding the factory strut mounts on... not going to shear off and it would take a hell of an axial load to snap four bolts arranged like that unless they were made of cheese.

 

Hmm...

To be more specific. The clamp load of four 1/4-20 bolts torqued to the grade 8 spec is in the neighborhood of 12,000lbs. Obviously you will not exceed that in service for that load path. The shear strength is quite similar and will not be exceeded either. The shear on the joint would be quite low anyway for that kind of clamp up.

 

We started making our older version caster/camber plates for the 3rd gen cars back in the early to mid 1990's.

 

Thanks guys. This is why I love TGO!

 

I don't want them to lock the thread again but that depends on what the bolts are threaded into aluminium is weaker than steel and how deep.

I don't think the bolts are a problem.

I just did not like seeing a company get bashed for the wrong reason. The bearings should be pressed in that may be a problem. Still not confirmed by UMI.

 

I have just been enlightened

Do you have any pictures of them? I would, for historical sake, be very interested in seeing them. i had no idea someone had done this then. I bought my car in 92 (1987 RS) and remember searching for parts for it back then and found nothing. I cam onto TGO about '97-'98 range from what I recall, I think it had just started up about that time.

Dean

edit- PS my interest stumbled into these car with knowing and growing up around Guldstrands shop in Thunder alley. I rode in his shootout car against herb Adams and remebered as a kid the draw I had towards the car even though I was influenced my entire life with Corvette's. When the car I bought came up for sale by a relative (1st owner from 1987) I jumped on it and bought it in 1992. I know Dick loved that car even though his heart had to stay with the Corvette market so he never really developed anything for it.

I made the rear multileaf spring clamps on at that time my father's 68 vette when I was 15 years old in about 1982, Dick copied them and started selling them

 

When I purchased the Spohn strut mounts and their rear coil-over set-up with the plate (first pic), I decided why not order just the plate for the front (second pic) that was part of the front coil-over set-up.

Brian

 

i think you have my statement a little mixed Brian...lol, I was not refering to the bottom side of the strut tower, I ment the bottom side of the bearing. But i fully agree that is a nice way to strengthen the strut tower area. I worked with Spohn on a few phone consultations about the coilover setup several years back. That rear reinforcement plate is the exact prototype design I gave him, I have the original renderings on my other computer I sent him because I was talking to him about how I was going to use a rear coilover and what I had done already to address the rear weakness both top and bottom mounts. The front was Steves idea. I did however suggest to him to use the Torrington thrust beaings since the coil spring assembly always has to rotate with steering wheel imputs. That is the only thing I do not like about coilovers on a 3rd gen frontend. I was hoping he would offer to send me one to test for him but he never did. If I recall, KAT was the test mule becasue he was an employee plus East Coast, I am on the other side of the world to him.

 

I didn't mix up the bearing statement. Just thought I'd throw the strengthening bit in the discussion. I'm not always as clear as I think I am.

 

you and me both brother!!!

 

Dumb question but did you install the strut with the stock dust cover? I have J&M mounts with Koni and I could not reuse the dust cover with these mounts, though with the stock mounts it fit just fine but once I put on the J&M's I tried to reuse them ( cause I really dont like seeing the yellow of the struts from the side view of my car) the shaft would not protrude high enough for the nut to catch.

 

I know the pictures are on here, saw them when I bought my J & M mounts. Someone had put a post on here with pictures around 2007 - 2008

 

I remember these from circa summer 2004. It was the first design by Hotparts I knew off and they did not favor well in lowered vehicle ride height travel. The struts were bottoming out and slamming against them bending the units. People started shimming them off the strut tower with spacers.
https://www.thirdgen.org/forums/atta...ster-plate.jpg

Here is a few pics of my car back in about 2001. Karl Hunter (designer) and Chickeman(A racer he Sponsored) actually ran the first two units Karl made. Karl then did a special run of 20 of them for various members here on TGO. I polished mine becaue they did come raw dull aluminum.

 

Interesting strut tower brace setup in that third picture. What's the diagonal brace on the driver's side connect to?


Unrelated note: I'd be curious as to how the Founder's strut mounts are constructed due to their price and popularity... might be good to have that out in the open for those in the market.

 

LOL- It's not hooked to anything- its apart in the picture because the STB is removed. I showed this picture becasue you can see them better since I was working on the carand had the crossbar off.

Founders? Like Chinesse crap. Tell me how a company can make a profit selling a unit that it's entirety cost less than the bearing only that I ran in mine? hope that answers you question. They sell because most people shop price not quality.

 

The bearings are a tight fit in the founders units I recently purchased.

 

Johnny, I was refering to te quality of metal (strength and weight)used in the bearings and their products(though the mount weight is not an issue since its sprung weight- but I was speaking in terms of their other products also that are unsprung weight)

What ever berings they are using have to be chinese crap at that price. The fact it fits tight is good, you can hopefully swap out another spec bearing of quality when it goes bad. I have a strong feeling my car would have wasted their bearings in one hard day of driving. I went through more expensive ones in 3 weeks. The can't be using $35-40 good quality bearings in each side for the price the sell a pair of mounts for. more like they are sourcing the cheapest ones they can find so they can turn a little profit.

you always get what you pay for unless someone is taking a loss.

Anyone else ever try welding a piece of metal bar stock from Home Depot? I tried that once in a pinch...emphasis on the words Tried & Once. Talk about crap metal

 

Understand, my reply was simply to the person that asked how the Founders were made. They come from the same source as J&M from what I have heard.