Loud bang on launch

[Heaten m90]

I see, well “bump stops” is definitely more of an appropriate nomenclature for these units, but they do look like yellow cakes and are so not racecar esk

 

[teeje]

I see, well “bump stops” is definitely more of an appropriate nomenclature for these units, but they do look like yellow cakes and are so not racecar esk

I did cut them down a notch

Sent from my SM-N950U1 using Tapatalk

 

[Mustang dog]

I used to have a loud clunk, on acceleration from a start. It was because I had a worn out differential mount bushing. Once that was changed no more clunk.

 

[Unexplodedcow]

Read the install manual I provided. As it states that is a one time use bolt. That is why they send a new one with the Upper relocation bracket. 200 ft/lb is a ton of torque. So if you removed that upper bracket for whatever reason, you may wish to replace the bolt as well as verify that the torque is properly set.And don't forget to check the lower bolts that go up through the bottom to ensure they are torqued to 85 ft/lb. Again this is all assuming for whatever reason you removed the stock bracket to install the aftermarket UCA.

The LCA bolts are only torqued to 129 ft/lb but they as well are considered to be a one time use. People reuse them as I have. But when it comes to torque levels at 200 ft/lb where it is specified one time use I become much more compliant. It's not a TTY application bolt (which should never ever be reused) but the level of torque being placed upon it when it is tightened is a mass amount.

The shop manual definitely states one time use, and Ford has gone that route with many of their bolts (including the front suspension bits). They is no claim that the bolts are torque to yield, though, which is interesting.

I measured a used and new front LCA forward bolt; they measured basically the same, minus some slightly different machining, using a micrometer. I then installed the new bolt, torqued to spec, and drove the car around normally for a bit. Eventually, I loosened it up and decided to check how much it had yielded, if at all. There was zero yielding. I think most of the spec is "CYA" on Ford's part, and possibly related to the use of nyloc nuts. I ended up testing other bolts later, including the rear UCA forward bolt, and noticed there was no change in length, which indicates no yielding. I've reused bolts, and haven't had anything loosen up, either.

That forward bolt is also considerably larger than the rear LCA bolts, or pretty much any other bolt in the suspension, and if it's not yielding, I'm not too worried about it. If we wanted to get heady about the topic, we can search for what steel is used, along with what hardness, and consider the tension the bolt is under. After that, it becomes a simpler matter of converting tension into psi, and compare that to the rated tensile strength of the bolt. Chances are it's not even close to the yielding strength.

...just some thoughts on this. New bolts never hurt anyone.

 

[teeje]

Im still scratching my head on this. I got under the car and didnt see anything as in any wear spots if it were hitting. I torqued the upper bolt as much as i cold. I havent been able to replicate it yet but if its still there is this a possibility of a bad differential? I doubt it but It may be a possibility. Backlash seems fine to me. Drive shaft doesnt look like its hitting. Its gonna go on a lift today so ill take some pics. Can someone link that poly axle housing bushing? I havent been able to find it. Also, as far as the UCA mount goes, the bolt that goes through the bracket and to the control arm, doesnt seem to have play. But yet ive heard something about using washers? I treid to move it back and forth with a pry bar and it didnt move.


EDIT: One thing I forgot to mention, when I replaced my sway bar end link bushings, they do have play (not on the bolt itself but side to side in the mount) maybe this can contribute to it?

 

[bl817]

https://prothane.com/vehicle-applications/vehicle-applications-ford/

6-315. you need to reuse the metal shell and gut out the rubber. a 1 1/2" hole saw and same size wire wheel does the trick. good luck

 

[Unexplodedcow]

I went with the BMR one when my stock upper bushing was tearing: http://m.bmrsuspension.com/?page=products&productid=781

I haven't put a ton of miles on it yet, but it feels solid, no real increase in vibration (though the roto joint UCA does plenty).

 

[RED09GT]

Is the stock upper bracket compatible with aftermarket UCA's?

I thought that the hole size was too big and that causes a loud clunking noise.

No matter how much you tighten the bolt, this won't go away until you get an aftermarket upper bracket.

 

[RED09GT]

Here is what I am talking about, look for Kelly from BMR's post and that makes it clear:
http://www.s197forum.com/threads/steed-upper-control-arm-mount.110677/