In need of some advice on chassis rails, apologies if these sound a bit dum! I came across by chance tonight of some hidden issues (see picture)
Right so the first question: Should body filler be used at all to cover up welds on chassis, as I found mine too have been!
Second question: I think this body filler had been to cover up rust! so will cut this out and put in fresh steel and get it done properly this time! Is the thickness same as other areas on the body 1.5mm or are the chassis rails thicker?
Thanks
No, body filler should not be used.
I do not have the steel thickness to hand but get a loan of a micrometre to check it. You can buy them from about £10 or less
Thanks thought that would be the case!
Will look at picking one up so can measure it.
That looks like original finish. Are you sure that is powdery filler and not more rubbery seam sealer/underseal? In any event a real shame. The MK1/Eunos has not tended to suffer the same fate as MK2 because the front chassis rails are single skin and do not have the very poorly designed second skin part inside the section as the MK2 does. The water trap is not there so generally the earlier cars do not rust through as yours has. Hopefully just a small isolated area affected. I would get right in there to make sure that all badly rusted metal is removed and patch with steel that is at least the guage of original. Not actually sure of original guage but 1.5mm sounds likely.
Looking at the photo again I see that this is not the chassis rail but the much weaker but supposedly stuctural members that run under the car. These are often damaged at MOT time when the car lifted on them without sufficient support. Nothing like the issue of the front chassis rails and easy to sort out. There are actually covers available, made by JASS I think.
Once repairs have been done I would treat those rails with waxoil or similar.
Years ago, the front of one of these anti-drum channels had taken a beating, enough to seperate the weld where the channel is double layers. I cleaned up, treated, slapped in some seam sealant and undersealed, thinking I’ll be back at that again in years to come. A couple of years ago, with the car on a lift, I had a chance to inspect this area. Still as I left it.
The photo is on the anti-drum channel (this is what Mazda calls it), not the subframe support front chassis rail. I believe that technically, it is not particularly structural, even though inspectors might not view it that way.
Hence, when people put a trolley jack under it, it collapses in a way that the chassis rail would never do so.
I think I read that MXRestorers was developing a replacement part that includes internal webbing to increase the strength.
Think wasn’t original filler by the fact that the fillers about 10mm thick!
Thanks for the advice and information. Yes is middle part so will be the structural member as you mention. Wasn’t sure if was part of chassis rails. Have seen the JASS covers, know people have been using them for making the car a bit more rigid.
Have got seamseal and waxoil so they will be going on once I’ve completed the repairs.