I seem to be finding all sorts of quirks and issues on my elderly GL. Having master cylinder issues, and when I look on Rock Auto I see a bunch of different ones and am not sure just which one I need for my 88 GL 5spd 4WD wagon. Most of the confusion for me seems to be the number of ports. If I am counting things right, mine has three lines connected to the master cylinder. The descriptions on Rock for three ports says for coupe and sedan, it does list the wagon ones with no description of ports, etc. Anyone know which OEM part number I should be looking at to cross reference? 

 

Eric

What is your "issue" exactly? Master cylinders rarely fail and are easily rebuilt. 

GD

My issue is that rare though it may be, my 32 year old master cylinder is bad. Yes I can rebuild, I had not decided which way to go, but it seems there are two different internal diameters 13/16" and 15/16" so I'm still stuck wanting to know which cylinder I'm looking for so even for a rebuild kit to order.

Just a guess but the different diameters may have to do with rather disc brakes all 4 wheels or just in the front. 

20 hours ago, john in KY said:

Just a guess but the different diameters may have to do with rather disc brakes all 4 wheels or just in the front. 

I believe that to be correct. That's the only change in the components at the wheels. Front calipers are all the same, just whether it has disc or drum in the rear. So I would assume the larger diameter one goes with the discs.

The cars without hill holder have 4 ports, and with hill holder have 3. And M10 inverted brake plug could adapt a 4-port to 3-.

43 minutes ago, Numbchux said:

I believe that to be correct. That's the only change in the components at the wheels. Front calipers are all the same, just whether it has disc or drum in the rear. So I would assume the larger diameter one goes with the discs.

The cars without hill holder have 4 ports, and with hill holder have 3. And M10 inverted brake plug could adapt a 4-port to 3-.

Thank you! It sounds like I'm on the right track then, mine does have the hill holder and appears to have 3 ports. I am disc front/drum rear (did any wagons come with 4 wheel discs? I'd love to convert)

 

Eric

Yes, the turbo models.  The XT and XT6 models used the same stuff.

1 hour ago, john in KY said:

Yes, the turbo models.  The XT and XT6 models used the same stuff.

Well...XT6 is a bit different being 5-lug.

oops.

Larger diameter will just result in less pedal travel and feel.

Order the rebuild kit from the dealer by the VIN. Problem solved. 

GD