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Changing Cradle Bushings by darbysan
Started on: 07-13-2015 06:39 PM
Replies: 8 (764 views)
Last post by: olejoedad on 07-14-2015 01:38 PM
darbysan
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Report this Post07-13-2015 06:39 PM Click Here to See the Profile for darbysanClick Here to Email darbysanSend a Private Message to darbysanEdit/Delete MessageReply w/QuoteDirect Link to This Post
I've spent a couple of hours searching, but couldn't answer my question( even though I thought I had seen it somewhere during my education process over the last few months)- so I pose it to the experts here! I'm in the process of replacing all the suspension parts ( bushings, ball joints, etc). I plan on replacing the cradle bushings when I do my engine swap later this summer, but wondered if I could/should go ahead and change out the cradle bushings now so I can get an alignment. My thought was whether the cradle bushings can be changed out without dropping the entire cradle/engine. I have a lift, and also have tall jack stands. Was thinking I could lower the front of the cradle just enough to get the two fronts out/in ( with the rear bushings still attached to the vehicle- maybe the bolts loosened up a bit), and then do the rears again by lowering the cradle just enough at the rear to replace those bushings ( essentially rotating the cradle on the front bushings).

If this wont work, or is a bad idea, I'll just wait until I drop the cradle for the engine swap.

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'87 GT in process, including GA / Seville brakes, Poly Suspension, '95 3800 Series 1 SC ( 225 hp ) T460e.

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notwohorns
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Report this Post07-13-2015 09:07 PM Click Here to See the Profile for notwohornsClick Here to Email notwohornsSend a Private Message to notwohornsEdit/Delete MessageReply w/QuoteDirect Link to This Post
Depends on what new bushings you are going to use. Metal bushings would be okay if lower the front of the cradle but with poly bushings, you have to burn the old rubber out of the sleeves.
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cmechmann
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Report this Post07-13-2015 09:33 PM Click Here to See the Profile for cmechmannClick Here to Email cmechmannSend a Private Message to cmechmannEdit/Delete MessageReply w/QuoteDirect Link to This Post
I did mine out of the car. The way I did them should work with the subframe dropped down about 6 inches. Used the 2 piece polys, so I wanted the outer sleeve in tact. Rather than burning them out, I drilled them. Get a decent quality 1-1 1 1/4 hole saw. At least 3 inches deep. Take a 1/4 inch bit and drill a bunch of holes through the rubber. Then with the hole saw you want to take it slow biteing away a little at a time. Go in a 1/4 inch back out, go a 1/4 more back out. If you try to go too fast the rubber starts to get soft and binds the bit and melt on it before you have a chance to back out. Then you have to pry out and start again. Don't go all the way through. Go in one side about 1/2 way then go to the opposite side of the bushing for the rest. Once you are through you can cut/peel the rest of the rubber out with a sharp knife. Make a few cuts parallel to the sleeve, then peel. Took me about 10 mins a side on 28 year old front bushings. Took me longer to get the bolts out. If yours are frozen turn the bolt to get the sleeve to turn so you can get to the separation in the sleeve. Then take a small air chisel bit or pointed bit and open the sleeve a little to get some rust penetrant to travel in the sleeve. If not you are going to just spin the sleeve around and not get anywhere. The sleeve starts out as a flat piece of metal that they form to make a tube. When you install the new bushing apply anti seize on the shaft of the bolt (not the threads) to keep that from happening again.
On the rear ones, you need to make sure you can get it low enough to chip out all the old rust that grows in the plate on the top side of the subframe and coat real good with a rust inhibitor/paint before you put the new bushings in.
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Dennis LaGrua
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Report this Post07-13-2015 09:36 PM Click Here to See the Profile for Dennis LaGruaClick Here to Email Dennis LaGruaSend a Private Message to Dennis LaGruaEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by darbysan:

I've spent a couple of hours searching, but couldn't answer my question( even though I thought I had seen it somewhere during my education process over the last few months)- so I pose it to the experts here! I'm in the process of replacing all the suspension parts ( bushings, ball joints, etc). I plan on replacing the cradle bushings when I do my engine swap later this summer, but wondered if I could/should go ahead and change out the cradle bushings now so I can get an alignment. My thought was whether the cradle bushings can be changed out without dropping the entire cradle/engine. I have a lift, and also have tall jack stands. Was thinking I could lower the front of the cradle just enough to get the two fronts out/in ( with the rear bushings still attached to the vehicle- maybe the bolts loosened up a bit), and then do the rears again by lowering the cradle just enough at the rear to replace those bushings ( essentially rotating the cradle on the front bushings).

If this wont work, or is a bad idea, I'll just wait until I drop the cradle for the engine swap.



When you drop the cradle you may have to adjust the alignment. If you replace the struts you will definitely need an alignment. Its easy to change the rear cradle bushings by dropping down the cradle rear next to impossible to change the front bushings with the cradle in the car. Most 84-87 owners replace the cradle bushings with poly or aluminum. The 88's cradles are solid mounted.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Flotech Afterburner Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite.
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olejoedad
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Report this Post07-13-2015 11:34 PM Click Here to See the Profile for olejoedadClick Here to Email olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by darbysan:

I've spent a couple of hours searching, but couldn't answer my question( even though I thought I had seen it somewhere during my education process over the last few months)- so I pose it to the experts here! I'm in the process of replacing all the suspension parts ( bushings, ball joints, etc). I plan on replacing the cradle bushings when I do my engine swap later this summer, but wondered if I could/should go ahead and change out the cradle bushings now so I can get an alignment. My thought was whether the cradle bushings can be changed out without dropping the entire cradle/engine. I have a lift, and also have tall jack stands. Was thinking I could lower the front of the cradle just enough to get the two fronts out/in ( with the rear bushings still attached to the vehicle- maybe the bolts loosened up a bit), and then do the rears again by lowering the cradle just enough at the rear to replace those bushings ( essentially rotating the cradle on the front bushings).

If this wont work, or is a bad idea, I'll just wait until I drop the cradle for the engine swap.



Yes, your method will work. The lift is really a plus when doing it this way.
Front cradle bushing removal is difficult, but can be accomplished without heat.
Get the cradle down enough for access and go at the front bushings with a drill and a long bit. Its a pain and takes a while, but it can be done.
If you have experience burning out bushings, its a matter of liquifying the bond between the metal sleeve and the rubber, then they can be popped out with a hammer without actual flames.
Still, it is stinky and the fumes can't be good for you....

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peterh
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Report this Post07-14-2015 11:07 AM Click Here to See the Profile for peterhClick Here to Email peterhSend a Private Message to peterhEdit/Delete MessageReply w/QuoteDirect Link to This Post
I did it on my 1986 years ago on a garage floor. A lift makes it easier but the front bushings take some time to get out as others as suggested.
Made a huge difference when I put the poly bushings in, before back end was all over the road.
Have fun!
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Tony Kania
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Report this Post07-14-2015 12:23 PM Click Here to See the Profile for Tony KaniaSend a Private Message to Tony KaniaEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by olejoedad:


...



I drilled my front cradle mounts out.

Heat is the easiest, but remember where your flame is, and the location of rubber gas hoses, belts, and wiring. Having someone heat the metal while force is applied to the rubber bushing on one side is the best. Like stated, less chance of the rubber catching on fire. Kind of like a flaming, dripping, gelatinous napalm marshmallow when that happens.
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darbysan
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Report this Post07-14-2015 12:39 PM Click Here to See the Profile for darbysanClick Here to Email darbysanSend a Private Message to darbysanEdit/Delete MessageReply w/QuoteDirect Link to This Post
Sounds like it's worth a try. I generally use the drill method on the A-arm bushings, so I'll try that for the front ones. I agree that flame and gas do not make a good mix.

Any issues with stuff up top- Ground straps and dogbone come to mind. anything else that might need removing before dropping the cradle 4-6".
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olejoedad
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Report this Post07-14-2015 01:38 PM Click Here to See the Profile for olejoedadClick Here to Email olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post
Just lower it the minimum distance needed and monitor the wires and hoses....
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