how do you know which (front/rear) mount is shot?

[fenixus]

hi there,

about to replace top engine moving rod (aka dog bone) on my 5S-FE once i get the OEM part. I'm suspecting that by now i have more than 1 blown mount. dog bone is visibly cracked, that's easy to diagnose. completely clueless about others. bottom mounts aren't cheap, so looking for a way of determining the truly guilty one (that if replacing dog bone does not help cure my case of reverse vibrations).

... but how about the others ? I mean front and rear. by looking at them ... well ... they look normal.

what tests (shifting gears and observing engine movement i suppose) do you run to determine which mount needs to be replaced ?

e.g. when you shift to reverse and engine side (front, rear, top, etc.) is moving excessively to this or that direction.

asking because maybe there is and "official" guide for finding a busted mount which I don't know of.

cheers and thanks.

[Kenny_McCormic]

Brake torque it, Put in drive, hold brake and apply some throttle, have buddy watch for excessive movement, then go to reverse and repeat.

[fenixus]

thanks that's basically what i was doing in first place. but how do you distinguish which one is blown? i'm sorry, i'm not fully getting it. also i think it can be done by 1 person IF parking brake is holding solid strong (plus maybe wheel chocks for better safety) while throttle can be applied from under the hood.

does it mean when in forward gear and applying throttle (with brakes applied) engine moves (where, front or rear) it points to a mount blown (where front or rear) ? please explain in plain English. thanks Kenny_McCormic.

[Kenny_McCormic]

No you have to lock the front wheels up, need two people. I don't have the motor in front of me right now but drive torques it one way and reverse the other, you will see what i mean if you do it, the area closes to the bad mount will lift up more than the rest of the power plant(this tests transmission mounts too).

[fenixus]

ok i understand. however i did my fouled version of test with rear wheels locked (wifey didn't want to come hihi). and here are results (might be fouled as you noted):

Drive:
when applying throttle minimally i see engine moving towards the cabin and it moves around 1'' backwards (mind slight throttle). i could also see front mount moving with engine a bit. i could not see rear mount much though.

Reverse:
when applying throttle minimally i see engine moving towards the grille and it moves around 1'' forwards (mind slight throttle). i could not really see front mount moving with engine. a vibrating noise started coming from behind the engine (not sure if top or bottom), also i could see top of engine vibrating.
i touched the top mount and vibrations were minimal. when touching front mount top bolt i could feel a lot of vibrations, but when touching mount's body itself it was quite still.

on top of that please mind top mount is supposedly blown (the horizontal rubber ring piece is cracked, vertical one looks good though).

any ideas what it means or test was making not much sense at all?

you can take a look at my engine mounts diagram here:
http://www.toyodiy.com/parts/p_U_200....html?hl=12363

[CJCride]

Tell wifey it's a safety thing and you are doing for her own good.
They usually reluctantly buy that one.

[carsrus]

The dog bone mount doesnt really do much. Theres no weight on it, its only there to dampen some vibrations.

If the problems really bad, then its probally not the dog bone.

[fenixus]

Originally Posted by CJCride

Tell wifey it's a safety thing and you are doing for her own good.
They usually reluctantly buy that one.

true
however those circuits do not run properly if wifey is chatting with a girlfriend over the phone LOL

Originally Posted by carsrus

The dog bone mount doesnt really do much. Theres no weight on it, its only there to dampen some vibrations.

If the problems really bad, then its probally not the dog bone.

yeah, that's what i figured. also it might that dog bone actually blows as a second one after one of bottom mounts fails and starts transferring vibrations to car's body IMHO... time will tell I guess.

it's just sad to hear this nice ride clunking every time i put it in reverse... i think if dog bone doesn't help (and others cannot say anything solid) I will start planning on replacing the rear mount, probably in Spring though (working on car outside). i really do not think the front mount is the case, however it might be that both are shot ... i guess that's what you pay for those moments of joy during aggressive driving (plus tickets if any) heh.