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Discussion Starter · #1 · (Edited)
I hope this helps some people out but you do it at your own risk.

This is my first how-to, it explains how to replace the crossmember mounts on a 99' P11 MT. Since automatics have the same mounts it should be good for that. I'm not too familiar with P10's but I suspect it's same/similar. Feedback/corrections welcome!

Search terms: engine mounts, motor mounts, howto, how to, crossmember, cross member, xmember, x-member

What you need:
Make sure you have all the stuff you need before you start as it will make the job a heck of a lot easier!

1) 2 Jacks
2) A total of at least 3 jackstands (2 for the car and one for the engine)
3) PBBlaster or equivelent (penetrating liquid)
4) Some patience
5) Couple of hours
6) A friend to help (preferred)
7) A long 2x4 and a saw
8) Anti-seize
9) wheel chocks

What to do

1) First thing is you need to do is get the front wheels off and the car jacked up to working height. So, as usual e-brake it, chock rear wheels, jack up the front and place the jackstands

The general idea here is to prop the engine up on the oil pan and on the transmission using a jack/jackstands and then removing the entire crossmember, pulling it out and then replacing the 2 mounts on it and then reinstalling the crossmember with the new mounts already on it.

2) Take a look at what you're working with.
  • Each mount is connected to the engine with a long bolt that goes horizontally. The front mount as a NUT on the driver's side. The rear mount has a welded nut. It's not that you have to cut it off or anything, it's just part of the engine bracket. You do not remove it by any means. When you put it back together you'll be threading the center bolt back through it again.
  • Each mount is connected to the cross member with 2 bolts, you can really see these bolts, nor do you have to worry about them. You'll be able to see them and have easy access to them once you've dropped the crossmember
  • The cross member is held onto the frame with 4 bolts (2 in the front and 2 in the rear)

3) SPRAY everything with PB blaster, don't be shy. These bolts are under the car so they see their fair share of water. At this point, it's probably a good idea to mention that I used airtools and given the tightness of the location of many of the bolts, it would have been difficult to get everything off. If you're going to use handtools be cautious not to snap bolts and definitely have a breaker bar handy.

4) Now you're ready to get the engine supported. The 2 places I used were under the oil pan and under the transmission. This is where you need the 2x4 or 2x6. You'll really need 2 pieces. If they're not already cut, cut them now to a reasonable lenght (couple of feet at the most).

5) Repeat step #3

6) Place a 2x4 ontop of your floor jack and then position it such that it's under the oil pan. Jack the oil pan up until you can kind of see the engine moving a little bit. Now place a jackstand with a 2x4 under the transmission to support that side of the engine. Lower the jack under the oil pan a bit until you feel you have equal pressure on both the jack (oil pan) and the jackstand (tranny). I used the center of the oil pan and there happened to be a square flat surface on the tranny what was perfect for the 2x4.

One other note: remember you are trying to jack the engine NOT THE ENTIRE CAR. So watch your jacking

7) Repeat step #3

8) The engine should now be supported fairly well and you are ready for your next task which is to crack loose the center bolt that goes through the middle of each mount. This is a pretty important step. For this step, just crack the bolt to make sure that you can get it loose.

9) You are now ready to remove the center bolts. The reason step 8 and 9 are separate is because the process of removing the bolt tells you whether you've appropriately supported the weight of the engine. First go ahead and ratchet them out until you're beyond the threads (rear) or the nut comes off (front). Now take the bolts out. The bolts should SLIDE out or be rubber malleted out but it should be smooth. If it's taking a lot of effort or a lot of hammering then the engine isn't supported.

If you've got it supported correctly the engine shouldn't be pushing down on these bolts. If you need to, ratchet these center bolts until they are reasonably tight and then go back to step #6 and do it again.

Once you've got the rear bolt out and the front bolt/nut combination, you're ready to remove the four bolts that hold the crossmember to the frame.

10) This is where a second jack is helpful, Jackup the center of the cross member (towards the back, beyond the bend in it) very lightly so that when you remove the crossmember bolts the crossmember won't just fall

11) Remove the 2 front bolts and the 2 rear bolts

12) Lower the jack on the crossmember slowly and grab the crossmember. At this point you should be hold this crossmember in your hands, the engine should supported on the jack/jackstand comibination

13) Now you can actually replace the mounts. Each mount is held on by 2 bolts. The rear one is the diamond shaped one.

14) Remove the 2 bolts and replace each mount. MAKE sure that the new mount is facing forward, there is an arrow that points forward. Make sure you look up the torque specification for the bolts (see attached FSM screenshot)

15) Clean it up and admire the new mounts, ooooooooooo

16) Now time to get everything reinstalled, first slide the crossmember into place. You can use the jack to hold the crossmember in place or have a friend hold it while you finger thread the 4 bolts that hold the crossmember to the frame. Put a little never seize on them

17) Now that the crossmember is suspended, fully reinstall the center bolts that go through the mount. Make sure it's line up properly and they should slide right on through (a little bit of rubber malleting will help). Never seize is probably a good idea here.

18) Tighten the center bolts, again watch your torques.

19) Tighten the 4 crossmember bolts, watch your torques.

20) Lower the jack that was propping up the crossmember

21) Raise the jack under the oil pan, remove the tranny jackstand, lower oilpan jack. Remove all tools. It's important to do all of this stuff slowly and deliberately. Everything is back together so it should be solid but just be careful.

22) Check torques again.

ENJOY NEW MOUNTS!


 

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Prince of Joy
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So watch your jacking
Hehe :rdevil:


Good writeup. A few things to add:

1. You dont really need to support the engine in two places. Just use the flat spot on the transmission as you described and this is plenty to support the motor. I never put any pressure on the oil pan -- ever.

2. The horizontal bolts will also bind if you lift the motor too much. There's a sweet spot where the motor is supported but not lifting on the car. You have to find this spot with your jack.

3. I wouldnt tighten down any bolts until all 6 are threaded. This gives you play to work with.

4. Always (ALWAYS) finger tighten the vertical bolts that support the crossmember. NEVER start right away with the ratchet. Many people have stripped the threads in the frame and regret it later.

5. The clearance is a lot tighter when you have solid mounts. It takes some trial and error to install all 6 bolts. I cant remember the exact order that worked for me, but I always worked from the rear of the car forward.




- Greg -
 

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The motor mount behind the engine has a welded nut? Which nut is it? It's welded to the cross member or through the mount itself? Do you need to use a Dremel (or othher) tool to cut it off?
 

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Discussion Starter · #5 ·
biomimetic said:
The motor mount behind the engine has a welded nut? Which nut is it? It's welded to the cross member or through the mount itself? Do you need to use a Dremel (or othher) tool to cut it off?
I called it a welded nut. It is part of the bracket that is on the engine itself, no need to cut it off or anything. Just remove the bolt and then the x-member will be loose there, no need to cut or anything.

That nut stays there (it's part of the engine bracket) and then you'll thread the bolt back into it when you put everything back together. THis is unlike the front one where the nut is loose and you have to hang onto it.

Hope that clears it up a bit
 

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why do you need to take off the front wheels? is it really important? cause i plan on just rolling the car up on like these mini ramps on each side of the car to raise it. hope you know what kind of ramp im talking about.

ps. getting ready to do the motor mounts this weekend :x hope all goes well without air tools. ima soak the bolts with wd-40 tonight and all day tomorrow. hope it works :x and can you tell me what the numbers mean on the diagram. i search it up but lost the site that told me. i know it tells you the size of wrench to use and it tells you how much torque you need to put the bolts back right? i hope im not wrong.
 

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Discussion Starter · #7 ·
ericc said:
why do you need to take off the front wheels? is it really important? cause i plan on just rolling the car up on like these mini ramps on each side of the car to raise it. hope you know what kind of ramp im talking about.

ps. getting ready to do the motor mounts this weekend :x hope all goes well without air tools. ima soak the bolts with wd-40 tonight and all day tomorrow. hope it works :x and can you tell me what the numbers mean on the diagram. i search it up but lost the site that told me. i know it tells you the size of wrench to use and it tells you how much torque you need to put the bolts back right? i hope im not wrong.
I had the wheels off to do the brakes. I don't think you HAVE TO jack the car up but it will give you a bit of working room and also depending on your ramps it might give you more vertical distance to get in there. No harm in putting it up on ramps and seeing if you can work there.

The last numbers give you a range in foot pounds for how much the torque the bolts should be at. For example the front bolt in the front mount is 44 51 ft lbs. of torque. See the little wrench and bolt in the diagram, that's the legend/key for the numbers, ft-lbs is last.

Last, you should use a penetrating oil like PB blaster or similar product. WD-40 is ok but it won't really help with seized bolts.
 

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You won't have much room to do anything under there with ramps. I had my car up on ramps to deal with my exhaust and it was a pain.

The P10 has a similar mount in the back but in the front, it's just a rubber piece that goes into a bracket on the crossmember. Other than that, the procedure is very close to the same.
 

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F**K im pissed my dad told me not to do this project because 1. im not experienced-this is my first car project 2. i dont have the right tools. im sure aalot of pb blaster will just do the job right?? like did you have problems taking off screws? he is worried its on too tight and i wont get the bolts off. and while im yanking the damn screws the car will shake and fall on me. rate this project...am i really over my head?!?! and should leave it to the pros and pay money that i can be saving??? or tackle it myself

ps. my dad does have experience with cars...worked in a garage for a period of time and i could say he might not know every thing in the car but he sure does know alot. he said he woouldnt even bother doing this project himself and letting me doing it myself is out of the picture.
 

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The biggest problem is getting to the bolts that hold the crossmember mounts to the brackets on the engine. Other than that, it's simple and should be doable with a $25 ratchet set, jackstands ($10?), and a good floor jack ($40-50). A $60-80 electric impact wrench could be helpful too, but might not be necessary (I used it though).

The other good news? You won't need too many other tools besides that either. I have those, a deep metric socket set (not necessary), some box-end wrenches, and a torque wrench, and I had no problems doing an engine swap with all that.
 

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I ordered 2 new crossmember bolts and 2 new rubber insulators and I was wondering if anyone you post a picture of their front crossmember set up so I know if mine is correct. The bolts do not pull the crossmember up flush with the rad core support and there is about a 1/2inch gap.

Also the rubber insulators have a cone shape and I am not sure which way to install. I installed cone down.

Thanks Guys!!
 

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Do you have the washers on the bolts?
 

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Yup...washers are part of the bolt. I guess what I need to know is if there is a small gap between the front crossmember and the rad support. The rubber insulators fill the gap but it seems a little big in my case. The bolts have about a 1 inch collar that does not have any threads so they cannot be tighten down anymore. I will try to post some pics.
 

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You want to use the exactly right size (17mm) 6 pt. socket on the crossmember bolts (which I believe are a fine thread), and be very careful not to strip/break them. The front radiator support is also prone to rust (if you live in the rust belt), and you should be checking that out while you've got the cross member off, maybe squirting some anti-corrosion spray in that box girder that forms the bottom of the radiator support.

This is a 2000 G20t with 100k miles in otherwise primo shape that lived in NJ before I got it (try not to cry... more reasons to be jealous of those living in the desert):





And to prevent this (this is a marine product pricily available at boat stores):

 

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My Rad Support looked exactly like that with a crack down between the bolts. I am in the process of installing the new support and replacing alot of stuff while I am at it. I had to cut off the old crossmember bolts as they were rusted to the Rad Support nuts which had become detached (also due to rust) from the Support. I really think there is a defect with the Rad Supports on 99-00 P11 as the rust is isolated to this area and extremly bad.
 

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Yup...washers are part of the bolt. I guess what I need to know is if there is a small gap between the front crossmember and the rad support. The rubber insulators fill the gap but it seems a little big in my case. The bolts have about a 1 inch collar that does not have any threads so they cannot be tighten down anymore. I will try to post some pics.
The washers are actually not attached to the bolt, unless the P11 design is weirdly different from the P10. You can see them in Lysander's pictures -- they should go alllll the way over the rubber isolators. If they aren't on there, the isolators get chewed up (I know from experience). The crossmember also has too much room to move without them, hence why I asked.
 
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