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MG MGB Technical - Seat slat coating

Hello everyone,
Happy to be the owner since this summer of a car that features wooden parts :-)

I noted that the wooden slats under the seats have cracked and broken and just ordered two new pairs from MGOC Spares. According to the product info they are made of Sheesham hardwood (Dalbergia sissoo) but no information whether they have applied any finish at manufacture. Does not seem so.

Hence, do you have experiences and suggestions on what to use for coating? Articles in the BBS archives note that the slats may retain humidity, thus causing corrosion. What finish was applied on the original slats when cars left the factory?

The present ones are painted black; however, they seem rather home-made. Varnish I believe is likely to crack. Wood oil of some kind?

Many thanks,

Thomas
(MGB RD 1969)
T. Slätis

Thomas. Why the MGB had wooden seat packing strips is something of a mystery. I suspect that it was a hold over from an earlier time, just as the MGA had wooden floors as a hold over from the T series which used wooden frames. In any event, the use of the wooden packing strips is original and, if one is to have a show car that is never driven and all that matters is original correctness the use of the wooden packing strips is a good idea. But, only for a never driven show car.

For a car that is driven, the wooden packing strips and the two circular spacers that each uses should be replaced by an aluminum strip. This aluminum strip replaces two spacers and one wooden packing strip beneath each runner, does not get wet and have to dry out, will not warp, and can be painted to match the color of the carpeting. Paul Hunt used to have my article about how to do so on his website, "The Pages of Bee and Vee". I have used the aluminum packing strips for something over twenty years now with good success and, at one time, someone was commercially producing these strips (here in the US) after I had designed them. Do not know if any are still available. If not, relatively easy to make.

If you still want to use the wooden packing strips, an epoxy type coating will hold up best with the least chance of cracking.

Les
Les Bengtson

Agree completely Steve. The original system of wooden slats and metal spacers around the bolts worked fine in conjunction with original spec everything. What we find is that any mismatch (slat thickness, floor covering thickness, etc) results in distortion of the seat runner bolted to the floor.

Most common example is thick soft carpet in place of the original moulded rubber mats.

The runner distortion ranges from minor to major, enough to permanently deform the runner.
With the floor runner distorted it no longer slides freely through the seat runner.

We use 6mm alloy flatbar instead. It is rigid enough to spread the attachment loads without distortion, resulting in a much freer moving seat adjustment. And greater domestic harmony for those whose other halves are not the same height!

Flat bar width of 30mm is usually fine and looks better, but for better load spreading 40 and 50mm are options.
Paul Walbran

Les and Paul, Many thanks for prompt reactions and informative replies.

Les, your article is still posted (https://www.mgb-stuff.org.uk/bodytext.htm#rails) and I did a quick read. One problem I am likely to confront is that my "Bee" does not have a carpet under the seat, only rubber mats, which may may pose problems keeping the runner undistorted even with new slats. Depends largely on the height of the spacers. I see what I can do as a solid straight surface is imperative for the runners. Further down the line the intention is to purchase new carpets, which will be a new factor.

The runners do not move very well at the moment and the current broken slats may be the culprits. I also believe that cleaning the runners and putting some grease in them will work wonders. For the floor bolts I will use copper grease as they seem quite exposed to both vibration and moisture.

Frankly, as idiosyncratic as the wooden slats may be I find them quite charming. :-) Since I already bought them I will put them into use.

At present, I am still getting acquainted with the car. When I move to more sophisticated improvements I keep in mind what you mention Paul about the various dimension of aluminium slats. I should be able to have them custom made relatively easily.

The car service and repair present me with a steep learning curve. Thanks to both of you for helping me along.

—Thomas
T. Slätis

Thomas. The spacers used, that fit into two of the openings on the wooden packing strips, are made of pot metal and are about 1/4" thick (6.35mm). That is the only ridged contact between the seat runners and the packing strips. The aluminum strips provide full, ridged support along the entire length of the seat runner. Also, something I found after writing the first article, it is possible to use two small button head cap screws to attach the seat runners to the aluminum packing strip, making it much easier to install the seat, runners, and packing strip into the vehicle.

As to the rubber mats, I assume you mean the type that fit into the foot wells to spare damage and wear to the carpet. They are cut out to fit around the packing strips and will not influence your choice. There will be no difference in how wooden packing strips fit onto a bare floor as opposed to how the metal ones will fit. On carpet, the metal is stronger and will deflect less, making for easier adjustment.

I replace the wooden strips with aluminum on all four of the vehicles we have owned over the last 25 years and wish I had done that with earlier ones. If you are going to start out learning about your car, this would be a good thing to begin with.

Les
Les Bengtson

Les (not Steve, sorry for that - not quite sure how it happened) rubber was used as the original floor covering at least in the 70s, not carpet.

Thomas, the aluminium flatbar system Les outlines works well whatever the floor covering is, due to being much more rigid than the runner and so giving it proper support in the event of any floor/floor covering uneveness. However, if you have the original spec rubber mats, and the wooden slats and spacers are the correct thicknesses, then retaining the original system has a good chance of working well.

Whatever you do, tweak the runners until they are all good and true when sighted along.
Also, if the floor has been replaced with an aftermarket panel check that the mount hole spacings are the same front and rear of the runners, any out of parallel will be a problem.
Paul Walbran

According to Clausager, rubber mats were fitted until 1977, when carpets were fitted as standard, having been introduced on the Jubilee model in 1975.

My ‘67 still has its original rubber mats, wooden slats and spacers.
Dave O'Neill 2

My wood slats came in black 30 years ago, and are still sound despite some wet running each of those years, some a lot of wet running. Allowing the car to fully dry out after getting wet is pretty important for many areas of the car, not just this.

Good job they were wood as they didn't have the right holes to match my seat rails so metal would have been a bigger pain to modify with simple DIY tools. They fit round the spacers which are what supports the seat, and are thinner so sit on top of carpet or rubber mats with not much compression force. As to 'why?' Either they stop the rails bowing, or maybe it just fills in the gap that would be left for coins and the like to get stuck in.
paulh4

This thread was discussed between 04/09/2021 and 06/09/2021

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