Seats Sliding under Braking

[mmahon04]

Hey everyone,

I have an '88 911 3.2 with the factory power seats, and under heavier braking the whole seat (from seat bottom up) wants to slide forward. This only happens when someone is sitting in the seat (I suppose the extra momentum helps the seat move), and only under heavy braking. I'm still learning the quirks of the vehicle, and was unsure if this was a primitive form of seatbelt tensioner, or whether I should be checking into a problem with the seat rails. A lot of searching between here, Rennlist, and 6Speedonline has turned up nothing.

Thanks,
Matthew

[Oh Haha]

Believe it or not, that WASN'T a factory option.

I would start with the seat mounting bolts(4 of them, 1 at each corner of the seat rails).

I don't have power seats but I suppose the motor could have enough wear that it isn't holding a position.

[mmahon04]

Wayne,

Thanks for the heads up. The seats, when powered forward and backward, do make a groaning noise; my first thought was excessive slack in the cabling, or the motor burning out. I'll also check for bolt tightness this weekend, but in the meantime I'll line up the excessive solution of all new Recaro's.

Thanks,
Matthew

[ejp]

Matthew,

I've also got an '88 with power seats - and I found you post while searching for a solution. My seats position doesn't really move, rather, it feels like there is maybe 1/4 inch of back/forth play. Is this what you are experiencing, or does the seat actually move?

In any case, let me know if you find anything. I'll start with the four seat mounting bolts (easy target) and check if they're loose. Otherwise, this may have to wait until this winter, when I plan to pull the seats out and re-dye them - I'll go over everything and check for any loose bolts in the mechanisms.

[NYNick]

New Recaros as a fix? Wow.
I'd pull the seats and check them out. Four bolts and a connector.
Nick

[mmahon04]

Originally Posted by ejp

Matthew,

I've also got an '88 with power seats - and I found you post while searching for a solution. My seats position doesn't really move, rather, it feels like there is maybe 1/4 inch of back/forth play. Is this what you are experiencing, or does the seat actually move?

In any case, let me know if you find anything. I'll start with the four seat mounting bolts (easy target) and check if they're loose. Otherwise, this may have to wait until this winter, when I plan to pull the seats out and re-dye them - I'll go over everything and check for any loose bolts in the mechanisms.

Mine is back/forth like you stated, perhaps 1-1.5" total play. No lateral movement. natural position is back, but under braking (or when pushing the seat hard forward), it'll shift by amount above, before sliding/returning back. Checked the rail to car assembly (bolts tight), and also checked the rail to seat assembly (tight). It appears the excess play would be in whatever mechanism governs the movement of the seat rail along the chassis rail. I'm assuming the motor at this point; I get a groaning/light grinding noise under operation of the seats.

Originally Posted by NYNick

New Recaros as a fix? Wow.
I'd pull the seats and check them out. Four bolts and a connector.
Nick

Once you look at the pricing of re-upholstering and (assumedly) replacing the motor on each, Recaro's (Sportster's) are but a pittance more.

I'll be pulling the seats regardless to at least know what I'm dealing with. I'll report back when I get some free time to do this.

[ejp]

I haven't got into my seats yet, but I think that the power mechanism/motor can be accessed from underneath without reupholstering the seat. I hope that I'm not being wishful on this, but from what I can see while the seat is in the car, it looks fairly accessible.

...unless you just have your heart set on those shiny new Recaros

[mmahon04]

Originally Posted by ejp

I haven't got into my seats yet, but I think that the power mechanism/motor can be accessed from underneath without reupholstering the seat. I hope that I'm not being wishful on this, but from what I can see while the seat is in the car, it looks fairly accessible.

...unless you just have your heart set on those shiny new Recaros

Hah, yeah, looking back I didn't provide some details in my post. My seats need some upholstery love anyways, so that factors into my total "seat project" cost. Regarding the motor, it appears to be open access.

[ridege55]

Reviving this old thread. I recently purchased a 1988 Carrera with power seats and experiencing the same problem with both driver and passenger seats. Is there an adjustment with the motor that can be done? I checked the mounting bolts and they were fine. TIA

[76FJ55]

Same problem that plagues the 928. there are some plastic spacers on the adjuster mechanism. take a look at this Rennlist thread.

[ridege55]

^^ Thank you so much