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Front Subframe (K-frame) removal & install - 4ws & 2ws

9K views 4 replies 2 participants last post by  89ba4 
#1 ·
This is my first write up and also my first post on a forum. I tackled a project that I figured I could document and take pictures of as I went along. I couldn't find a good write up on this so I figured I would give back to the community.

Short story as to why I did this project.

I have a 1988 Si 4ws and a 1989 Si. The 88 is all stock and has 164,xxx miles. I got this car to be my daily so I just did a major tune up so it is running great. The 89 is modified and has 231,xxx miles. She is running great but, the rust is getting bad on quarters and rockers, exhaust rusted off at the flex pipe (straight headers now) and she could just use a break.







I ended up putting the 88 into a curb and bending the subframe and lower control arm. My stupid mistake....






I am attending college right now and don't have the funds for a subframe offline or from a parts car. I figured I could give my 89 a rest and have my 88 back for what I got it for, being a daily driver. After doing a bit of research on what exactly I was about to do, I thought what better way to spend my spring break. I allowed for plenty of extra time just in case something didn't go as planned. I completed it within 3 days.
Here is my write up on how to remove/swap/install a front subframe aka k-frame.

Necessities:
Tools- You will need a variety of tools. I'm not going to list all of the tools. If you are trying to attempt this job, you know you will need a wide variety of tools.
"Special tools":
Ball joint separator (pickle fork) - I rented one from Advance Auto.​
Line wrenches - for power steering lines​
Paint marker - marking steering alignment​
PB Blaster (penetrating oil) Always makes the job easier. One can is plenty for this job.
Jack stands
Wheel blocks
Room to work
Time and patience If you own a 3rd gen prelude you know by now to be ready for anything along the way.
Helping hand - At some points in this project it made it a lot easier to have an extra set of hands there to help.

First you need to make sure the wheels are blocked and the E-brake is pulled. I used a piece of 4x4 laying around. I break the lug nuts on the front loose while the car is still on the ground to make it easier.
Remove the front wheels.



I did this whole project without taking the spindle nuts off and disconnecting the cv shafts. I think it would have been easier if I would have but you live and you learn. The spindle nut is a 32mm.

The next step is to take apart the front suspension where it connects to the subframe and the steering rack.
This requires the tierod to come off the knuckle.
15mm



The lower control arm must be disconnected from the subframe.
17mm



I also had to swap the lower control arm on the drivers side as well. I had to remove the fork bolt (17mm), radius rod bolts(14mm), sway bar links (12mm??), and the lower ball joint (17 or 18mm). I rented a ball joint separator (pickle fork) from Advance Auto to separate the ball joint.
In this picture the lower ball joint nut is loose and the radius rod bolts are out. The fork bolt has not been removed. (soaking in PB blaster)



Sway bar end links removed


I then removed the sway bar and the center beam.
Sway bar end links should be disconnected at this point. The sway bar bushing brackets are held in by a 14mm.





The 6 center beam bolts are 14mm as well.





Taking a break form being under the car I began removing the intake tubing (10mm). The filter box and a resonator box are mounted to the subframe. The filter box is held in by 3 10mm nuts. I don't have pictures of all of these pieces. If it has a stock intake there are like 5-6 pieces of tubing that need to come off to get to them.



The circled hose comes off of the back of the filter box and leads to resonator box. I left this on when I dropped the subframe because the bolts are very difficult to get to.
I removed the bracket for the filter box so it wouldn't be in the way.(triangle with studs) 2-10mm bolts


I moved back underneath the car to disconnect the power steering lines. There is a cover over the steering box that is held in with 3 10mm bolts.


I went about this by tracing the lines that came off the steering box. If the lines were attached to the subframe, I left them attached and disconnected them where they were last attached to the subframe. Of the 4 lines, 2 were attached to the subframe and 2 weren't. I used needle nose pliers, screw driver and pick to get the hoses off.

Arrows pointing at lines to disconnect.

One line needed to be disconnected from the steering box, which was a 12mm. I used a set of line wrenches. You will need to guide this line when dropping the subframe.


While that was draining I started to disconnect the exhaust. I decided to drop the entire exhaust due to the bolts on the catalytic converter being so rusted. I removed the 4 (12 or 14 mm) nuts from the 4-2 flange.




One of the studs came out with the nut, but wasn't an issue.

I put a jack underneath the exhaust to hold it up. I then removed the bolts in the bracket holding the exhaust to the bottom of the engine.



I then sprayed all the rubber hangers with some pb blaster to lubricate them. They slid right off and I pulled the whole exhaust under and out the back. A helping hand might make this a bit easier.




Next I disconnected the steering column(s).
I used a paint marker to mark a line on the steering column so I could match it back up on install. The bottom bolt needs to be completely removed and the top bolt should be loosened to allow movement in the joint.




The 4ws steering shaft to the rear only goes in the front rack one way so there was no need for the paint mark. Same situation with the rear bolt being the one only loosened.


This is the bolt you want to take completely out.

The paint mark is from the factory. The second bolt is underneath the plastic cover.

At this point I went through and made sure everything was diconnected from the subframe. With a jack stand with a block of wood underneath the engine I removed the engine mount bolt (17mm).


Bolt has been removed.

I placed the jack with a block of wood on it underneath the rack and pinion. I started to remove the 4 (17mm) bolts holding the subframe in. I made sure to take them out evenly so the frame didn't bind on a single bolt as it started to drop. I would loosen all the bolts a little bit then drop the jack a little so I knew it was free and repeated this process till all the bolts were out.





This was one of the trickiest part of the project and this is where a helping hand might be most useful. Getting the the subframe free form both steering columns is the fun part. I also had some troubles with clearance for the air intake resonator box on the shift linkage.




And its out!!

The 89 doesn't have 4ws so I was going to swap the rack and pinon from the bent frame to the good frame.

I start to remove all of the power steering lines and take the rack and pinion out. You will need to disconnect all of the lines going into the steering box (10, 12, & 15mm).

Then you need to remove the lines from the frame itself. This is just a series of plastic clips.





Once all the lines and brackets are removed, the left tie rod end needs to be removed. Then the rack needs to be pushed in the right most position. This means if the rack were mounted in the car the wheels would be turned all the way to the left. The bolts (12mm) to the brackets can be removed and the rack will wiggle free. Slide the rack all the way to the right and the left tie rod should clear the subframe.





Once all of this is out and disconnected you can begin to swap over all the new parts in the reverse order. I suggest taking pictures to help remember exactly how things went together. Keeping your work space clean and organized is a huge help when trying to find bolts when trying to put everything back together.

I needed to do this process all over again to remove the subframe from my 89. However, the 89 doesn't have 4ws and I deleted the power steering a while ago. Those were the hardest things to deal with, so it was a breeze.

Make sure you have all the bolts and nuts tighten to the correct torque specs.

It is VERY IMPORTANT to get an alignment after you are finished. Almost all of my specs were out when I got an alignment. I hit the curb pretty hard…..

Here are some pictures of the damage:




Random pictures:




Please let me know what you guys think and if you have any questions.
 
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#2 ·
nice write-up you need to resize a few pics and rehost so they fit the screen.
 
#4 · (Edited)
all the pictures are showing up. most are perfect size. There are two that are very big. These are the ones that cause you to scroll right to see them. I have never used imgur yet. You can control size by the camera but I usually take full resolution pics then resize them to about 30% with paint or photoshop software before hosting. I am not real sure on pixel size. I don't take a lot of pics. Each camera takes different size I have a 8megapixel dslr. So just trial and error.

well they were showing up earlier most are not now. Not sure what you have done.
 
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