Help with knocking on front end supra96

[dini_the_owl]

hi,
just wondered if anyone had experienced any knocking issues on the supra front end when braking to a stop and pulling away again,i even get it when i reverse then brake and then when i pull off,i can also hear a similar knock when i make sharp turns.its getting really annoying and can oly assume it could be coming from the steering rack or front swaybar as it dosent seem to come from anywhere i can pin point like a loose shocker or caliper,evrything seems tight but i think it could be a bush or something gone....?any ideas would be appreciative.
thanks andy

[pwpanas]

Originally Posted by dini_the_owl

hi,
just wondered if anyone had experienced any knocking issues on the supra front end when braking to a stop and pulling away again,i even get it when i reverse then brake and then when i pull off,i can also hear a similar knock when i make sharp turns.its getting really annoying and can oly assume it could be coming from the steering rack or front swaybar as it dosent seem to come from anywhere i can pin point like a loose shocker or caliper,evrything seems tight but i think it could be a bush or something gone....?any ideas would be appreciative.
thanks andy

If it isn't a loose control arm (often alignment shops won't retighten them to the correct torque), then it's probably the motor mount(s):
http://www.mkiv.com/techarticles/fro...ise/index.html

[dini_the_owl]

Hi thanks for the post,
Somewhere along the line i had seen the thread you posted so i went out and purchased two new oem mounts with a view to curing this and hey presto...no luck,damn shame but i am running out of options.
by saying control arm do you mean the main arms that come from the shocker, or are you talking about the front anti roll bar,as i dont get the clunking when i go over bumps ets just on braking and taking off and sometimes when turning.
please let me know any other options or ways of checking,i have even tried to follow the car down the road with someone braking,just so i could feel the clunk or see any play but after nearly killing myself i gave it up.
thanks..

[pwpanas]

Originally Posted by dini_the_owl

Hi thanks for the post,
Somewhere along the line i had seen the thread you posted so i went out and purchased two new oem mounts with a view to curing this and hey presto...no luck,damn shame but i am running out of options.
by saying control arm do you mean the main arms that come from the shocker, or are you talking about the front anti roll bar,as i dont get the clunking when i go over bumps ets just on braking and taking off and sometimes when turning.
please let me know any other options or ways of checking,i have even tried to follow the car down the road with someone braking,just so i could feel the clunk or see any play but after nearly killing myself i gave it up.
thanks..

I'm not talking about the sway bar...that shouldn't make noise unless it was improperly installed/reinstalled. I'm talking about the lower control arms...the large moving roughly-curvy-Y-shaped bracket that the lower shock mount and the lower hub is bolted to. The bolts that connect these control arms to the frame are adjustable, in order to allow for alignment changes. If the tech that last did your algnment didn't retighten these bolts to oem specs, they may be sliding around within the 'play' that allows for alignment-adjustment. For example, the bolt connecting the control arm to the crossmember must be torqued to one hundred and sixty-six foot-pounds:
http://www.mkiv.com/manual/manualtt/...ement/ss-1.jpg
...for anything but a relatively heavy sportscar (eg. Supra, Viper, Vette, BMW M5, etc.), this torque spec is significantly above average. If the alignment 'tech' you took your car to is used to doing civics and maximas (imho) there's a significant possibility he got it wrong.

I'm sorry to hear that you wasted your hard-earned $ on new motor mounts that you didn't need...but, please note that the tech article on motor mounts describes the troubleshooting/diagnosis steps that you could have taken to make sure that was the problem:

...
To really isolate your individual problem, try the following (really)

Have a buddy to drive the car forward and back and load up the front end by braking at about 2-3 mph fairly hard and hold the brakes hard.

Then, have him/her drive the car backward 10-15 ft and brake fairly hard (this is not a beat the crap out of your car procedure)

Be sure to be standing next to the car and walk back and forth with the car so that you can hear the popping noise...which by the way will most likely be more apparent going backwards during this exercise.....

If you hear it under these conditions I would be 99% sure that its your motor mount, especially if you have a well maintained vehicle

If you want to take it another step , take a wooden paint extender pole or broom handle and have your buddy repeat the above braking drills, but on the reverse brake (where the pop should be occurring) walk with the car and have the pole 'square' on the motor mount (with hood up obviously)

If you hear the POP and you have the pole in the right place you will literally feel the POP up through your hand.

If it does vibrate crack a beer open and celebrate....
...

I can't help but be a bit curious: did you follow each and every one of these steps to the letter (especially the part with the broom handle) before you changed out your motor mounts? In general, I must urge you to go through all of the troubleshooting steps in tech article(s) and the TSRM before spending any $ on parts or installation labor...there's a science to automotive repair, maintenance, and modification work, which (from a big-picture perspective) generally represents the most cost-effective way to work on your car. Sure you'll get lucky occasionally with a shot in the dark, based on the guess that someone online might suggest...but that troubleshooting & best-guess diagnosis via typewritten descriptions on an internet forum is no substitute for having the car in-person to troubleshoot hands-on! Any mechanic worth their salt will tell you the same thing, imho.

[dini_the_owl]

hi,
Not a problem with spending dosh on some motor mounts,its probably better that i isolated them first anyway,i also do all my own repair work so there is no labour cost,i would just like it right if you know what i mean...lol
i will try the torque settings on the control arms and let you know of its progress.i am hoping it may well be so simple,it just seems like its both sides and there are so many bushes etc it could be by looking at it i just thought it may be a common thing.i will let you know and thanks again.

[pwpanas]

Originally Posted by dini_the_owl

hi,
Not a problem with spending dosh on some motor mounts,its probably better that i isolated them first anyway,i also do all my own repair work so there is no labour cost,i would just like it right if you know what i mean...lol
i will try the torque settings on the control arms and let you know of its progress.i am hoping it may well be so simple,it just seems like its both sides and there are so many bushes etc it could be by looking at it i just thought it may be a common thing.i will let you know and thanks again.

How many miles on your Supra?

Also note that if torquing the control arm bolts corrects the problem, you'll have to get it properly aligned, and then re-check the torque again after the re-alignment has been done...

[dini_the_owl]

hi,i have checked the torque settings on the control arm nuts and all is ok at 166,do you have any torque settings for the steering rack to sub frame mounts as i cannot seem to find anywhere.
thanks andy

[dini_the_owl]

by the way i have 68, 000 miles on my mk4
thanks andy

[pwpanas]

Originally Posted by dini_the_owl

hi,i have checked the torque settings on the control arm nuts and all is ok at 166,do you have any torque settings for the steering rack to sub frame mounts as i cannot seem to find anywhere.
thanks andy

To be honest, the best thing you can do is to get a copy of the TSRM for yourself. Please trust me when I say that it will pay for itself many times over. If you're interesed, a Toyota dealer that gives a discount to Supra owners is Jeff Watson (800)327-2087