Fitting replacement rear floor pans to your EJ or EH
Most of us that are rebuilding, restoring or just keeping our old Holdens on the road will have some rust in the floor pans. This is usually attributed to water leaking in through the rear window rubber that is old and perished. The water gets under the original rubber floor covering and ‘sweats’ until rust sets in badly.
It is more common to have to replace rear pans, so I have only got them shown here. Sedan, wagon, ute, van all have the same floorpans. The only difference being factory automatic models, which have a slightly different front pan, and the replacement which is for a manual needs to be fitted with slight modification. The basic principles of fitting them is the same for front also, and even for other model Holdens, especially HD-HR. Please remember that the pans are replacement only, and not original pressings, so some patience and skill is required to fit them to the point of being almost undetectable. It would cost about $200 a pan to fit them with overlap at a panel beater, up to $500 a pan if you want a really nice job butt welded and painted
First of all you should assess which pans and how badly rusted they are. Strip the surface on the inside back with a wire knot wheel on an angle grinder and then put a light under the car to see how many holes you have. Poke at the holes with a pointy and see how bad they are. Once the decision has been made to replace, pop your replacement over the original floor, press it down hard and see how much it covers. You may even need to trim slightly at this stage to sit it in neatly along all ridges and the inner sill. Mark it out with chalk or something you can see easily. This is the left hand rear pan in an EJ-EH
Thinking very clearly now, you must make sure your brake lines, fuel lines, wiring, handbrake cable, exhaust and anything else running under you car is removed. Cut the area previously marked, taking care to do the following. Cut only to the edge of the sill, not into it. Cut along the edge of the cross member the back holes of the front seat bolt to. Cut about 20mm in from the back seat cross member, making sure not to cut through the rear spring hanger, and also 20mm in from the line marked along the tail shaft hump. Basically cut less than you have to for now, as it is easier to trim a bit more than adding it back later. This is the cut I did with a 115mm angle grinder with a 2.5mm cutting disc.
This is what it looked like with the pan on the floor. Note the use of a jack stand for safety and to raise the vehicle high enough to work underneath later. Don’t throw the old pan out for now. If you are using original type seat belts, you will need to weld the seatbelt retainer nut into your new pan. Also If you are going for real originality, you will need to screw the ‘hat’ back on the floor pan where the drain hole is.
Once you have done the rough cut, trim the sill side back really neatly, leaving the lower lip if you wish. The new pans have the lip folded upwards, so it does not have to be removed, and if you seal the join really good, the old lip makes the pans look original still. Trim the edge near the front seat cross member back really neatly also. The pan can sit on top of this edge. The bit of floor still attached to the spring hanger has spot welds, and these can be ground off, and the section trimmed away carefully, again not cutting into the hanger. Keep trying the pan and trimming the back edge and the tunnel edge, until you have a 1mm gap on these two sides.
The trick now is to be patient and tack weld the pan in a bit at a time until you are happy it is in the position you require. Check underneath and see it is pushed down low enough to meet the spring hanger. The sill and front cross member sides can be stich welded, that is 1cm weld every 3cm. The other two sides should be butt welded. drill a couple of 5-6mm holes through the pan to the spring hanger and plug weld the pan to it also. Again making sure you have pressed it down low enough to meet it. Don’t forget on the right hand rear to weld the tag for the handbrake spring back on. This is the right hand rear
Once they are welded in, you can grind the welds back inside to remove any excess bumps. Underneath you can grind it all back smooth and linish it to get that original look. A bit of seam sealer along the sill and front seat cross member. You may wish to spray body deadener over the whole underneath and inside.
