MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB Technical - Seat Construction

I've unfortunately figured out why I have more head room in my B!

While chasing wires around the car and looking for more trouble I noticed that the back half of my seat foam essentially sets right on the floor.

I've looked at seat frames for sale on Ebay and I've looked at my seats. I cannot figure out what there is suppose to be to give the foam some resistence to sagging down to floor.

Is there some type of mess or wiring frame that was suppose to go along the underside of the seat from side to side or back to front to support the foam?

Thanks for your help.
R.W Anderson

Look in your Moss MGB info and you will see a rubber webbing that goes under the seat foam - not sure what year you have - the webbing changed over the years.

Good luck
J Delk

I believe there were two schemes to keep your - er - self off the floor. There was a webbed version and a diaphragm system. Both are interchangable, and most recommend the diaphragm as more robust. Use of a hair dryer is usually recommneded to aid getting the hooks installed. The seat foam itself may be compressed - these are NOT interchangable as they mate up to the seat cover. (And, over the years, the year of your car and the seat cover may have drifted!)

While tolerable for short runs, I once made a long trip with a fatigued bit of webbing, so that my lumbar "rested" against the firm steel bar at the rear of the seat. I required medical attention afterward, and served as motivation to repair the seat.
John Z

yep...you do NOT need new frames unless the frames are broken. I doubt seriously if they are!

New diaphragms and foams will do wonders...and you CAN do it yourself.

I've done so on my '78 MGB and my '69 MGC. The '68 MGC is next.

You will be AMAZED at the results.

rick ingram

usually just new diaphragm will be all you need, the new foams tend to be too high. I am still using the original foams in my car and they work well.
Stan Best

RW. To go along with what Stan posts, I installed new diaphrams, seat foams and covers on three of my cars. All of the foams had to be cut off 1.5" in the front tapering to 1.0" at the rear, for me to be able to see out of the roadsters or avoid having my head pressing against the roof of the GT.

The old foams were not in sufficiently good condition to re-use. The new foams seem to be somewhat harder, do not allow you to sink as much, as the original foams. But, it has been a long time since I sat on new, original foams and my memory may be at fault.

In any event, your problem can be cured with a little investment of time and money. The condition of the seat covers will tell you whether you need to replace them or not. I used the Moss seat covers and had them professionally installed. The upholstery shop declared them, "of good quality materials and well made". They do look nice and seem to be holding up well, but it will take several more years to make a definitive evaluation.

On my daughter's car, I had custom seat covers made rather than use the Moss covers as I did on my own roadster and GT. Overall cost was very similar to the Moss covers. Thus, should you decide you want "something special", as she did, a good upholstery shop is worth talking to. I have, over the years, become close friends with the owner and employee of the shop I frequent. Amazing what taking over a six pack of beer and spending an hour with them, a few times a month, can do in the way of custom work.

Les
Les Bengtson

Hi R.W.,
I was reluctant to rebuild my seats myself but after I did it once I realized how simple it is. It sounds like you don’t need new seat covers. This simplifies your task even more as you won’t even have to take the cover off of the seat back. The foams are always too thick so I would just replace the rubber underneath.
To do this there are 4 bolts holding the seat to the floor. Undo these, pull out the seat and turn upside-down. There are some metal clips holding the seat cover on. Pull these off with some pliers. Now you'll see how the rubber attaches to the seat frame with little metal hooks. Take off the old rubber and replace with new. You'll have to stretch the rubber to get the hooks to go back into the seat frame. now just place the seat cover material back over the bottom of the frame and press back on the clamps that hold it and bolt back in your car.

If you decide then after this you need new foams for the seat bottoms, you can order them and redo this process which really wont take too long the second time you do it. I do not recommend new foam at first as it is expensive and you will have to cut it to get the right height. I've tried to leave bags of cement in the seats overnight to press down the foam and stretch the rubber, but it is not a good solution.
Jeremy RG

Hi RW.
I forgot to add a hint. When putting the seats back in it may be difficult to line up the bolts because of carpeting etc. I once found a couple ways to make this easier.
Each seat has two frame rails that the seat slides back and forth on. I also put zip ties on these rails so they stayed in position on the seat frame during installation.
If I remember correctly I fished a piece of wire or zip tie up from underneath through the hole to see where the hole is. Then you can see where the hole is to line the seat rails up and put the bolt through. On either a midget or an MGB I once put the two bolts in from underneath so they stuck up like studs. THen place the seat in place on the two studs. Then I put the two front bolts down in properly from the top and then removed the two back ones and put them in properly form the top.
I dont remember the exact tricks I used, but I did take a seats out, replaced the rubber diaphram underneath both seats and bolted them back in the car in about 25 minutes each before a date.
Jeremy RG

Les & Jeremy, what did you use to cut the foam. I remember hearing years ago, but have never had to cut any foam, that an electric carving knife works well. Or did you just use a utility (Olfa) knife?

Derek Nicholson

Derek. The professionals, on the first set, used a cross-cut wood saw. On the second set, I used the saw "under supervision". The regularly use an electric carving knife when doing the final trimming of foam, both after cutting with a saw and when they have added glued on foam to a basically good seat with wear in only a small area. They did a lot of build up on the seats for my 77 Scout II as no new foams are available.

As to Jeremy's comments about seat installation, he has some good ideas. Never thought of using cable ties myself, but it might work very well. Paul Hunt's website, "The Pages of Bee and Vee" contains a tech article I wrote on replacing the two wooden packing strips and four aluminum/zinc spacers (per seat) with two strips of aluminum. All of the information should be there and, if necessary, you can contact me for assistance if you have problems. My latest versions, and I will write a new tech article this winter, is to make the aluminum packing strips, bolt them to the seat rails, and drill and tap both to take two 6-32 button head cap screws. When the screws are used to bolt the runners and the packing strips together, you go from having six pieces to get into alignment with the four holes to having two pieces to align. Makes for a much easier job of it.

Les
Les Bengtson

Agree with Rick.....recently replaced seat foams and webbing, and the difference in comfort, driving position and visibility is almost unbelievable. I WOULD replace the foam, the new ones are harder (denser) and would remain firmer for a longer time. I don't have problems with headroom and I'm not small. Maybe American foams are different from British supplied foams!
Joe

While on the subject of seats...

On of my seats is broken, if you recline it past 90 degrees it won't 'click' into place and falls backwards. Not taken them apart yet, but has anyone else found this?

Also does anyone know if the silver deckchair type covers are available anywhere?

Cheers

Graham
G Lewis

Graham,

Don't know about your seat problem, but as far as I am aware the deckchair design is not available anymore.
Joe

This thread was discussed between 18/09/2006 and 20/09/2006

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.