1970 GT (1.9L) Front Calipers Conversion

[opelgt1976]

Has anyone ever tried to use 1976 Opel Isuzu Calipers on a GT?

The picture on auto zone looks pretty close, but I need to check the specs.

[BQS4]

Originally Posted by opelgt1976 Has anyone ever tried to use 1976 Opel Isuzu Calipers on a GT? The picture on auto zone looks pretty close, but I need to check the specs.

Well, you CAN use the calipers off a BMW 320i and bolt them right on your GT.

[blancojp]

Originally Posted by opelgt1976 Has anyone ever tried to use 1976 Opel Isuzu Calipers on a GT? The picture on auto zone looks pretty close, but I need to check the specs.

You can use them if you re-drill the mounting holes on the caliper and grind off a bump on the rear of the spindle that is located between the mounting tabs.

Rock auto has the caliper fully loaded with pads for $28.00 plus shipping.

[lezliewk]

I have a new 76 Isuzu caliper right behind me on the floor, I was going to use on a Manta, But I found a new set on ebay for the manta. It is about the same, except where the brake line goes in, Needs a little bending to fit right If someone wants it,Pay shipping and it is yours. PM me

[opelgt1976]

Originally Posted by BQS4 Well, you CAN use the calipers off a BMW 320i and bolt them right on your GT.

I have seen this mentioned several places on this site, but have a question. Since my car is a 1970...

-Are the 320i calipers similar in size to the '75 "Big Brakes"?
-What rotors do you use with the BMW calipers?
-Can I still run stock wheels? (13" I think)

Is there a true bolt on for the 1970 Calipers? i.e. could use stock rotors?

[BQS4]

Originally Posted by opelgt1976 I have seen this mentioned several places on this site, but have a question. Since my car is a 1970... -Are the 320i calipers similar in size to the '75 "Big Brakes"? -What rotors do you use with the BMW calipers? -Can I still run stock wheels? (13" I think) Is there a true bolt on for the 1970 Calipers? i.e. could use stock rotors?

the BMW caliper are the SAME as the 75 Opel ones
You use the stock 75 Opel rotor
Yes you can run 13" stock wheel, my wife has big 75 brakes on her 74 Sportwagon, as I was the one that put them on, and she ran her stock rally wheels for over a year till I swapped her over to custom wheels

[opelgt1976]

Originally Posted by BQS4 the BMW caliper are the SAME as the 75 Opel ones You use the stock 75 Opel rotor Yes you can run 13" stock wheel, my wife has big 75 brakes on her 74 Sportwagon, as I was the one that put them on, and she ran her stock rally wheels for over a year till I swapped her over to custom wheels

One last question...I thought the BMW rotors where vented (thicker than the Opel) Are there some BMW calipers that are setup for thinner rotors?

[blancojp]

Originally Posted by BQS4 the BMW caliper are the SAME as the 75 Opel ones You use the stock 75 Opel rotor Yes you can run 13" stock wheel, my wife has big 75 brakes on her 74 Sportwagon, as I was the one that put them on, and she ran her stock rally wheels for over a year till I swapped her over to custom wheels

The BMW 320I solid rotor caliper is very close, but not the same as a '75 Opel caliper. Yes they do have the same 89mm mounting arrangement and yes they are both made for a 12.5mm width rotor however, the BMW unit has a 4mm increase in heigth to compensate for a rotor 255mm in diameter. This means you will have a small pad overhang of 4mm with a '75 rotor and 8.5mm with the stock GT rotor.

A better alternative is to use the 320I Girling caliper for vented rotors and use a '91 Celica 255mm front rotor with a 3/8" spacer. You can still use your stock wheels with this combination and you will also increase cooling and braking efficiency over the '75 setup by 20%.

If you do not mind having 4 mills of lip on your pads after a few thousand miles then you are right, they are the same.

Then again, I could be having senior moment and be totaly wrong....