Lowering the driver's seat mounts

[DaddyGlenn]

I figured someone might find my experiences useful. So, I'll be documenting my efforts to lower the drivers seat mounts.

First thing is to remove the fuel lines from the tunnel. They are nylon/plastic and will melt during the welding process if left in place.

There are two lines, supply and return. At the front of the car, they connect to the fuel tank and the fuel pump and at the rear they connect to other fuel lines where they exit the tunnel.

Disconnect the lines, front and rear. I have the engine/transmission out so there was plenty of room in the rear.






Remove the peddles, center console and carpet or whatever you need to to see the front of the tunnel on the inside. Again, I have the advantage of having the interior gutted.

At each end of the tunnel are grommets the fuel lines go through. You can poke them out from the inside (behind the peddles and in the shifter connector access) or using brute force push them in from the outside.

Tie a string around the rear of one fuel line and working from the front pull it out. Disconnect the string leaving it in place to use to pull the fuel line back in when you are done.

Sorry, I didn't grab any photos of these steps.

With the fuel lines out, it is time to remove the old seat mounts. Again, my interior was already gutted so you will have to remove seats, carpet etc. if you haven't already.

On the door side, grind away the welds around the edges and drill out the two spot welds. On the tunnel side drill out the spot welds. I counted 36. Use your grinder to smooth everything and remove the paint where the new seat mounts will go.



Sorry no picture of driver's side but you can see it in the picture below.

Next I ran string from the passenger side lining up both passenger side seat mounting holes to create a guide for the driver's side.




In the picture above, you can see the results of my next step. Using the strings as guides, I marked a line 2 inches below the original height. I did this on both sides.

[DaddyGlenn]

I came to the 2" decision by building an adjustable template.



I used a scrap of particle board I had and cut it to fit the space between the tunnel and door side. I installed carriage bolts with washers and nuts to make it height adjustable then mounted the seat. I place the whole contraption in the car then adjusted the nuts on the carriage bolts until I had the lowest height that would allow seat to clear the sides. I then removed the seat and measured the distance from the string to the template. Needless to say, the strings had to be moved out of the way during the height adjutments.

Here are a few more shots of the template.



Holes for mounting the seat...




I then got some 1.5 x 1/8" angle steel and cut four 2" sections. These will become the mounting tabs. I set them on the template in the car to mark the center point for the mounting holes. I grab some pictures later.

And.... that is as far as I have gotten. The weekend is over. I will update this thread as I make more progress.

[DaddyGlenn]

Had a chance to put in a little more time on this project.

Here is a shot of how the tab will sit.



Using the wood template, I laid out the tabs and marked and drilled 5/16" holes. Then not being confident of my measurements, I decided to steal from the Porsche engineers. I drilled out the spot welds to reuse the left side "nuts" and carriers.





I used one to mark the metal I needed to remove to expand the hole.



Made the hole bigger and welded the carrier with "nut" on the tab.




That should make mounting the seats a tad easier.

[JAR0023]

Originally Posted by DaddyGlenn

Had a chance to put in a little more time on this project.

Here is a shot of how the tab will sit.

Are you going to box this or somehow support the inside edge of this tab? You've gone from two full length rails, convoluted for strength and attached with 30+ spot welds to four tabs made from simple angle and welded on the vertical. If you have any meat on your bones I sense bending in your future. Beautiful work so far but I'm not sure I'd trust my deuce and a quarter a$$ to simple angle stock.

Don't mean to come of *****y, I just need a beer.

J

[DaddyGlenn]

Valid question, J. And one that still runs through my mind. I got the tab idea from searches of this forum. Others have done it.

I would love to hear from others who have tried this approach. It is not too late for me to change my plans.

[jplucas]

Even if it doesn't bend under normal usage it will most likely tear out from the unibody in a crash situation when it will see 10-20 times the load!

Reinforce it while you have everything apart.

[Porsche Head]

Agree about better/more support tab material to distribute the load however the idea and approach are very clever!!!

I built drop down brackets (l shape) but might try to do something like yours and weld to the side rahter then bolt to the top mounts. My 72 had a different mount welded on the tunnel side, I cut those off to mount the drop down l shaped brackets to an alum plate for the seat.

[DaddyGlenn]

Thanks guys, for making me rethink my approach. I did a bunch of measuring of the two different seats I will be using and re-searched the forums. I'm went with a beefier structure.



I had to contour the bottom of the angle stock....



Here is the result ready for seats....

[HenrikL]

Thanks! I'm 6 feet 4" myself and having some thoughts about doing something similar.

Have you put the fuel lines back into the tunnel? That is the part that frightens me the most.

[DaddyGlenn]

Originally Posted by HenrikL

Thanks! I'm 6 feet 4" myself and having some thoughts about doing something similar.

Have you put the fuel lines back into the tunnel? That is the part that frightens me the most.

No, not yet. I'll document that too when I get to it. This is just part of a major rebuild so I won't put the lines back in until after I do the other seat mounts and repaint the car and some other interior work.

My height is in my middle so headroom was the goal for the driver side. My wife is 6'2" and all leg so I'll be moving the passenger side down and back to accommodate her legginess.

[island911]

Impressive. but I can't help but think that raising the seat rails on the seat would be easier. ...and then, just for the driver.

[RSTarga]

Change out all those rubber lines while your in there, they look a little old, just preventative maintenance and much easier with the car apart now.

[DaddyGlenn]

Originally Posted by RSTarga

Change out all those rubber lines while your in there, they look a little old, just preventative maintenance and much easier with the car apart now.

Got new ones sitting on the shelf....

[rattlsnak]

I just went to home depot and bought a piece of 5/8 square steel stock, cut out the old rails, and cut and welded two pieces of the bars into place crossways, drilled two holes in each, done. The whole process took @ 2 hours..