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Jesse's Front Pan Repair

Jesse Silverman is a young Bay Area 912 owner that has just finished high school and has now gone off to college at Duke University. This summer he replaced his front suspension pan. This is his story.

When I purchased my car I was not completely informed on all the places old 912's rust, most importantly in the front area near the battery. This area is particularly crucial because it supports the front suspension, and could collapse while you are driving, which wouldn't be good. After discovering that I had this problem, I knew I had to deal with it before the car was safe to drive. There is a lot of information on this repair online, but because I had little knowledge of the car and welding I had trouble interpreting the best route to take in order to fix my car. I hope that I can provide other people with the knowledge to understand this repair fully, but remember to read the whole piece before getting started.

This is my personal experience, for some people the project may be significantly easier and for others more difficult. The first step in repairing the suspension pan is to decide on whether or not to do the project yourself. Unless you have experience welding and working on cars this is a very difficult project. When I started the project I had almost no experience in either area. My personal recommendation is that if you need your car on a daily or fairly frequent basis, this project is best left to a professional. If you don't need your car on a daily basis, I would then ask myself these two questions, do I have more time than money? And, do I want to learn how to do this kind of repair?

I cannot count the number of hours I spent doing this project, but it was upwards of 60 hours. A lot of my time was tedious work, some of which could have been avoided with the right tools and knowledge. Here is the description of my project as best as I can remember it, I have included some photos I took along the way.

Things you will need:

  1. Suspension Pan $190
  2. Gas Tank Support $30
  3. Gas Tank Seal $5
  4. 4.5 Angle Grinder(great for lots of different projects) $45
  5. MIG welder with argon/CO2 gas shielding $70 a day plus gas
  6. Protective equipment(Clear face shield, gloves, welding mask and if you choose a respirator)
  7. Grinding wheels $2
  8. Por-15 $10
  9. Paint $5

    Total: $357+
jesse01 The first step is to get the parts you will be needing, mainly the suspension pan and the gas tank support (Yes, you need both!). I purchased mine from Restoration Design. I was very satisfied with their customer support, but as I learned later my piece was manufactured incorrectly. The three holes that the a-arm bolts to were not spaced right, something I learned after welding the pan in(Doh!). Their explanation was that it happens once in 50 pans or so and is outsourced to a laser alignment center. I found this to be a little disturbing, so I urge you to check that your piece is made correctly beforehand by bolting everything together before welding. The other issue I had with fit was that the gas tank support piece was slightly different than mine and had to be slightly modified to fit correctly. I believe this problem occurs because I have a short wheel base car and the support may have changed in later years. I would probably say that most places you buy from will give good results, but if you can buy locally do so, that way you have someone you can deal with in person. You must also buy a gas tank seal, this is just some sticky foam that can be had at Kragen for $5.
jesse02 After obtaining the parts, you have to set your car up for the repair. The difficulty in this is that the front of the car must be supported behind the front suspension. I used a 4x4 and put carpeting on top of it and then placing it under the front floor pan with 4 jack stands underneath the wood, you must have more than two because other wise the wood will bow. In terms of setting the height, make sure there is enough room to be able to lie underneath to weld and grind.
jesse03 After setting the car up, the next step is to remove the front bumper and the A-arms. Here is one way to remove the A-arms. Take off the bolts and support at the front of a-arms. Next unbolt the two large bolts with cotter pins that attach the A-arm to the shock absorber through the ball joint. I left the ball joint and shock dangling from the upper mount the whole time, with brake attached and all. After the a-arms have been freed of these 5 bolts on each side it is necessary to remove the torsion bar. The removal is done by taking the rubber end caps off, and then removing the c-clip from in front of the bars. To get mine out I had to tap on the bar from the other end. When the torsion bar is out the a-arms should just slide off. To remove the bumper there should be three bolts on an adaptor on each side and then a fourth bolt that attaches near the outside of the fender wall.
jesse04 After the suspension has been removed it is time to remove the gas tank. First drain the gas tank through the drain plug at the lower rear end of the tank. Continue by removing all hoses from the tank, the engine feeder hose on the bottom, the vent hose and the gas filler hose on the top. Once the tank is drained and all hoses detached there are three clips that are bolted down with Allen head screws, one in the front middle and one on each side(if it helps, the clips were originally painted gray). Once all the clips are removed, more than likely the gas tank will be fairly stuck. What I did to remove the tank was to get a 2x4 and place it on a jack underneath the tank. I had someone else hold down the front of the car while I jacked up the gas tank. It should eventually pop out.
jesse05 Now that everything attached to the suspension pan has been removed, the old pan is ready to come out. I found this to be one of the most difficult parts of the entire project. I would first recommend looking at your car and trying to fully understand which pieces of metal have to stay, and which have to be removed. Hold your new pan up to try and visualize exactly what you will be replacing. One part I must warn you about is that between the pan and the gas tank support there is a piece of metal that is hidden and sandwiched. The best way to describe it is as a continuation of the vertical metal that runs perpendicular to the pan on each side.
jesse06 Another important point to remember is to leave one side of each flange along where the suspension pan goes, because that is what you are going to weld the new pan to. Once you have the removal visualized it is time to start cutting. I began by using a sawzall to get rid of the big areas I knew I wouldn't need, but be careful!
jesse07 Once the large areas of metal were gone I used two methods to get the rest of the old pan out. Each has it's pros and cons. The first method I tried was to use a spot weld drill to drill out each and every spot weld. The problem I encountered was that on the lower flanges the bit would always catch an edge and break, and the bits are not cheap.
jesse08 The other method I used was to grind away all the flanges. This was very tedious but ended up working well, just make sure to only grind away the flange you don't want.
jesse09 Be careful because it is easier to remove metal than it is to put new metal on. So when in doubt on whether something should be removed, don't do it until you are absolutely positive it is on one of the two new pieces you are going to weld in. Also make sure to measure the length of the pan and cut the old one out a little long so the new one would overlap if installed (Later you can grind it down more, but for now leave a little extra).
jesse10 Before putting the new pan in the car it needs to be prepared for installation. The first thing I did was spray both pieces with weld-through primer. Not only does this help in the welding process but it also provides some extra protection for hidden areas you can't paint later. After painting the pans, I had to drill holes so that the pan can later be plug welded into place.
jesse11 There will be three rows of holes on the pan and the gas tank support will be drilled all along the perimeter. It is a good idea to look at the placement of the old spot welds before you start drilling. On the pan you will need to drill holes along the two flanges then along the front lip of the pan.
jesse12 Notice how on your car the front is not perfectly flat so the holes in the lip must be in clusters of about four, but use your car as reference for cluster positioning.

For the holes I used a 3/16 in. drill bit and placed the holes ~1 in. apart. Once you have drilled the pan and the gas tank support there are several areas to drill on the car itself. The first is on each side where there is a flange that runs along the center of the two "legs" of the pan. The other place to drill is along the bottom edge of the front wall of the car.
jesse13 Once the old suspension pan is out and the new one prepped, the pan must be fit into place. There should be a tight fit, so it should be difficult to get the new one in by hand. I needed two people for this part, one person would help support and position the pan while the other used a wooden block with some type of lever underneath to push the pan into place.
jesse14 I also needed to use a long piece of wood inside the luggage compartment to press the front of the pan all the way forward in the car.
jesse15 Once in place I used a combination of c-clamps and vice grips to hold it in. After it is fit in place I recommend checking the fit of the suspension, something I neglected to do and paid for later. When checking fit all you need is the a-arms and the front mounting plates. Just slide the a-arm in and bolt it to the new suspension pan. If everything seems to bolt together quickly you should tack weld the pan into place.

Once the parts are tack welded you can remove all the clamps.
jesse16 In order to duplicate the factory spot welds as close as possible with a MIG welder I used a method called plug welding. The reason for drilling all the holes in the pan was for the plug welding. In order to use this method you must have a MIG welder with a gas shield, the flux core will not give you the results you want.

Once you have the welder, the plug welding is fairly simple. I found the easiest and strongest method was to first use scrap metal to get the settings right on the machine, you should get a crackling noise as you weld. After the welder is set, take your welder and put the wire in the center of a hole you drilled and just hit the button. It should heat up the piece of metal in back and then the molten metal will spread out and fill the hole. I found this to be best because if you start too close to the edge of the circle you drilled the metal melts away faster and you don't get as good penetration to the piece of metal in back. Make sure to keep switching sides as you weld so that you don't get one area too hot.
jesse17 When all of the holes are plugged you will need to do four main bead welds, here may be more areas you need weld up more. Two at the rear where the back end of the pan meets the car and two at the front, right before the pan goes vertical against the front of the car.
jesse18 The final welding step is to put the gas tank support on and plug weld it into place, remember to grind down any old welds that will prevent good fit of the gas tank support.
jesse19 Just to warn you, don,t depend on my description as a welding guide, it is not all inclusive and everyone's situation will be different.
jesse20 I was able to do it as a novice welder. I had taken a class and had guidance from someone with more experience than me. If you don't feel comfortable welding, than this project or the welding portion of the project is not for you.

After finishing welding take a 4.5 in. angle grinder and take all your welds down to be flush with the metal around them. This will provide a nice finish to the project. My welds did not look perfect, but my final product looked nice after grinding. After I finished grinding I put down two coats of por-15 and then covered that with a coat of standard black paint. On the bottom I sprayed on some undercoat. I then reinstalled the gas tank, suspension and bumper and the car was ready to go. I saved myself $1500, but I did put a lot of time and effort in, I learned a lot and had a great time and isn't what this is all about anyway?
Last modified: Mon, 18 Aug 2003

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