More sedan work...... lots of panel replacement in the pipeline. It takes more effort to remove old useable panels off a wreck than buy brand new ones. If only they were still available.
First we start with the left replacement sill. Pic 1 removing the sealant to expose the spot welds. Pic 2, in typical Mazda style, clean on the outside, surface rust on the inside.
Removing the center pillar.
Unpicked, takes longer than you think. Patience goes a long way to ensure the panel is not damaged. I will also be using the front of the inner sill as that section is rusted out on both sides of the car, it has a unique shape that would be difficult and time consuming to make a replacement section. I'll also be using the outer seat sill panel area as it's very common for the inner sills to crack where the seat mounts are spot welded, more on that further down.
The dog leg is also a problem area. Generally speaking coupes will have far more serious rust issues in the rear of the car than sedans. That's not to say sedans can't rust just as bad ! The dog leg section will clean up nicely. Pic 2, the right sill panel is missing the dog leg so I bought a used quarter to make my life easier. Thanks Ray you're a legend
Both left and right outer seat mounts are stuffed on the car including. I've got one replacement that being the on the drivers side. Pic 1 the good replacement. Pic 2 the cracked original. If I can't find a good left side I'll make a template and have it laser cut. These are all typical 808/Rx3 problems. In it's race car guise the race seat was mounted to the floor with a reinforcement plate and not on the original mounts.
Pic 1, normally hidden from view but this is where the inner sill panel cracks behind the spot welded seat mounts. Some cars are worse than others. If you're a big fella chances are there will be cracks in the inner sill which normally can't be seen without removing the outer panel. The other panel that sits in front of the cracked area makes up the inner B pillar panel. Pic 2, Right inner and outer replacement sill unpicked...
Again, the sills look good on the outside but are a little rusty on the inside. All these parts will be cleaned up further, beated where damaged from using jacks in the wrong place then sent away to be sand blasted spotless. Pic 2, I saved the the cap that seals the sill panel from the rear within the wheel tub. This will be used to make new replacements.
Next the donor quarter cut for bits and pieces. Pic 2, a little on removing spot welds. The drill bits are generally available in 2 lengths. What you see are 2 different brands. These are the only 2 brands that I will use, from my experience all the others I have tried are garbage. The left one is the Alpha brand and is the cheaper of the two. They work and last quite well. The gold colour one is made by Suttons and if my budget was unlimited it would be the pick of the two. They are sightly more expensive, the cost adds up because they don't last forever. In my opinion they give a nicer cut and the pivot point does less damage. The down side is they don't last quite as long as the Alpha brand and they are more fragile so to speak. It's not uncommon for the small pivot to chip off which renders the bit useless as they then wonder all over the place.
I was asked on how to use the bits because some people still drill through both panels. First I drill a small pilot hole in the center of each spot weld. I think its debatable whether cutting compound or oil prolongs the life of the bits as you're drilling out hardened steel from the spot weld process. The bits definitely don't last forever, you'll probably use one for each sill panel for example. The bit will still work but will be past it's best. The best way to understand why they don't last is imagine drilling through panel steel, easy right ? Now try drilling through a MIG weld.
Removing spot welds in Mazda's is quite easy. First trick is let the bit do the cutting. There's no need to apply much pressure. Now keep at eye on the spot weld, in a Mazda it normally will change to an orange colour when you hit the center point. Mazda engineered the panels to rust (the orange colour) so people like me would have an easier time restoring them 40 years after the year of manufacture, serious
If you apply to much pressure while drilling you'll miss the colour change. Sometimes you'll see the primer coat instead of rust depending on how the car was kept. Once you get to this point, use a wide flat screw driver to crack the join. Also have a think about how the panel will be re attached, that will change what gets a hole (plug weld) and what doesn't (spot weld).
Last for now... the door shells are stripped, aligned and installed back on the car. What I'll be doing here is taking measurements around the doors and front guard when it goes on so when the remainder to the sill comes off the car for the replacement sills I have good reference points. The original doors fit very well on this car. Once the sills are done I'm still thinking removing at least one A pillar, I don't want to but it may be the only way to get the repair I want. I'll make that decision later on after the cowl comes off. Once that's done the I'll grind the edges off the door skins, send the shells away for blasting and then the new skins can go on.
I can now see this is going to take a while #-o