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Discussion Starter · #1 ·
i want to start gathering parts for the bmw brake conversion for my GT.... is there a thread on here about it?? ive decided to buy loaded rebuilt calipers and new rotors.... i need to find 2 hubs.... anyone know where i can get some used ones?? are there any additional parts needed besides the new brake lines??

has anyone else done this conversion?? how do you like the brakes?? was it worth it??

Thanks!!

Joe Van Wagnen
71 2.4L GT
 

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You will need to remember a few items.

>Track in front will be widened by approx. 3/4" total....so choose wheels carefully.

>Rotors need to be machined to a smaller diameter to fit under the calipers...the Opel mounting flange is in a different location than the BMW's. Same diameter as a 1975 rotor in fact.

>Calipers must be shimmed aprox. .030" so they are centered on rotors.

Much has been written about this conversion in the 'Blitz" newsletter over the years. Perhaps back issues are available.

Stopping power is identical to 1975 brakes, seeing how the caliper, pad and rotor surface are identical. Pad choice will determine ultimate C.F. They are, however, far more fade resistant because of the ventilated rotors. I've had a set since 1985, have only replaced pads a few times, and turned rotors twice. Been on three different cars of mine.

Bob
 

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Discussion Starter · #3 ·
>Track in front will be widened by approx. 3/4" total....so choose wheels carefully.


lets see the recomended offset for 15x7 wheels should be 15-20 mm.... so which way do you add the 3/8"??? + or -??? to the offset
 

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Joe,

Here's the link you want, thanks to Otto Bartsch!

As for the wheel offset, Otto's modification requires a spacer to allow the wheel to clear the caliper. So you can actually use a wheel with MORE offset, such as would fit a typical rice burner. Instead of a 15x7 wheel requiring a 20 mm positive offset, you can use a VERY available 38 mm offset wheel. At least at the front. If you want to use the same wheel at the rear, just use the same spacer. And longer studs at both ends, of course!
 

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:confused: Does one have a picture of this brake conversion. I bought an opel that did not come with brakes installed, but came with a new set of calipers. front are from the BMW 320i. and the rear is from an '82 280zx.

Anyway, it would really help to have a picture of the finished product.
 

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Weird, the link USED to work, but the file isn't there anymore. I have asked Otto Bartsch (the originator of the EXCELLENT photo that describes the conversion) where it went. In the meantime, I happened to save a copy, so here it is....
 

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brake line hanger?

The brake line hanger used with the stock GT caliper doesn't seem to fit onto the larger BMW calipers.
From what I can tell from Otto's photo there is no steel brake line between the caliper and the braided brake hose? Does this sound correct? A male / Female hose rather than F/F?

Thanks,
Bob
 

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what not to use?

Ok,
As difficult as it may be to believe I'm still working on my front brake upgrade. After much reading thru everything I can find about the vented brake setup, I began collecting the pieces.
I bought vented rotors for the 1977 BMW 320i - at least I bought the parts listed for that particular car, making a note to get the vented and not solid disks.
Not knowing what I'm doing as usual, I was puzzled by the fit (or lack) of these new rotors on my stock opel hubs.
I realize that some have used the BMW hub instead of the Opel hub - mounting to the BMW hub from the front 4x100 wheel studs - and to the Opel hub from the back with the 4 12-point bolts.

Are there 2 versions of the 1977 BMW vented rotor? If so, I think I've found the version NOT to buy!!
#34 11 1 119 112

The center bore is too small for the Opel hub and mounting holes are 4x100.

Does anyone have the part number for the correct version? Or do I need to have these machined?

Thanks for your help!
Bob
 

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Still working on the engine

:confused: It's not going to be too long now before I am able to start working on the brakes. A short background, I bought my car from a guy that was less that honest about what I was buying. Among other things, I was told that the brakes where all new and ready to be bolted on. However I found that the front brakes have the vented rotors, but non-vented calipers. I am going to try to put non-vented disks and just use the non-vented calipers, save the vented rotors for a future upgrade. Unless of course someone from here has any idea why this is not even worth attempting. BTW non of the machining has been done yet. I'll be taking plenty of pictures for anyone attempting this in the future.:confused:

Oh, I'll check my vented rotors when I get home to see if I have a partnumber on them for you.
 

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Rotor supplier?

I just e-mailed the guys at Bavarian Autosport for specifics, but they have rotors listed for the 77 BMW 320i for $47.95, almost half of what Advance Auto wants for them. They also claim to have drilled and slotted rotors for the same. I'll update when I find out more.
 

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Post part numbers when done?

I've been following this thread for a while now, I'm kind of confused as far as what works and what doesn't.

Can someone state clearly the following:

1) Part numbers used (year/model would help)
2) Modifications done to make it work
3) Part source/prices if possible

I think this info will help a lot of people out there.

Thanks!
 

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Don't know how to explain, but...

OK, the part # Bob has listed above, 34-11-1-119-112, should be the correct part # for this project, and it cross references to a more common Beck Arney # 0831537. This rotor is supposed to have a 75mm center bore and 98mm bolt circle to bolt to the rear of the Opel hub. I have checked the cross reference 7 times with 5 different locations, and none of them look like the rotor in Bob's picture, they all look like Otto's picture.

The one Bob's picture looks to be a 34-11-1-154-747, which would be for a BMW 318, but that is pure guess based on the picture.

The correct rotor is available at my local Advance Auto for $67, my local import shop for $60, or on line at www.bavauto.com for $47.95. Bavarian Autosport also stocks:

34 11 1 119 112 BRAKE DISC-FT E21 47.95

34 11 1 119 112U BRAKE DISC SET-FT E21 194.95 1 pair Ultimate drilled/slotted rotors

34 11 1 119 112D BRAKE DISC SET-FT E21 174.95 1 pair Drilled rotors

34 11 1 119 112S BRAKE DISC SET-FT E21 174.95 1 pair Slotted rotors

They also stock several compounds of pads, and Mike Bailey, one of their customer service reps, has been truely awesome about researching parts for me. They are located out of Portsmouth, NH and have a great free catalog.

That aside, the calipers are $199.00 each new from Bavarian Autosport, so that might be a bit cost prohibitive. Advance Auto stocks Raybestos part #'s: RC3911 and RC3912 for loaded calipers with pads and pins at $59.99 each with a $30 core. Or you could get their A1 Cardone part #'s 19876 and 19877 for $74.99 with a $5 core and then get your own pads and try to find a set of caliper pins.

Aside from the calipers, pads, and rotors, the rest of the install shouldn't be much harder than a normal brake job. You will have to have the hub flange cut down as in the picture to clear the caliper and either hunt around for wheels that fit or add spacers to use the stock wheels. You could use the stock lines, both the rubber and the short hard line, but you might as well replace them while you're at this.

Obviously you will have to evaluate everything for yourself when you attempt something like this. I am doing something different on my own brakes on the Kadett, and as a result when you go down this road you'll have to get others to blame if it goes all wrong.

Good luck, and I hope this all helps.
 

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Thanks for the information!
Although, I actually ordered the pictured rotors from bavauto!

The box says:
34 11 1 119 112 DISC-FT,320I77,323I-82

So before anyone goes spending their 47.95 X 2 you may want to be sure you're getting the correct version.

...I wonder if brake discs are exchangable?...

Bob
 

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I know my brake rotors were 1977 320i, and were cut down to 9.625" OD to fit. Calipers are the same, 1977 320i. But as I said, I used the BMW hubs, not the Opel ones. This is obviously different than Otto's setup. I ground my calipers slightly, and used an 1/8" wheel spacer, and was able to use stock Opel steel wheels (4-spoke) with these brakes.

Bob L.
 
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Can anyone tell me if these BMW calipers will work for the "Big Brake" 1975 Ascona/Manta with solid disks? Or are they the vented rotor type? And if so, can I just get vented rotors and have the best of both worlds?

1 pair of Girling front brake calipers - rebuilt by UK brake part specialist AMK. Part # TCA 361 : Designed to fit BMW E21 3-series ['75-'83], Opel Rekord E ['78-'86], Vauxhall Carlton as well as other models/manufacturers; please refer to interchange catalogues for specific applications. These calipers were dry mounted one time to check wheel rim clearance/fit, but never fully installed or otherwise connected. Excellent condition though sold as-is. No Reserve. BMW part # 34 11 1 150 262.
 

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keith,

They should work fine. I saw that auction last night & was going to bid on them myself if no one else did. I have a used set of ATE & Girling calipers from the Pic-a-Part yard that need rebuilding. They are identical except for the "ATE" & big "G" stamped on them. They are for the NON-vented rotors, which the eBay ones are also. I was able to cross reference the BMW part #. I think he has the years wrong though as the E-21 (320i) wasn't available in 1975 & that Part # is for the 78-83 NON-vented rotor caliper.

Tom C
 

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Talk about resurrecting an old thread!

Does anyone know for sure the correct Brembo part number for the '77 BMW vented rotors? I just got B25234 from Tirerack for $25 each, but they are waaay off, over 1" wide instead of .81 and 10-3/4" diameter, made to fit over a 5 lug hub.

I ran a search of Brembo part numbers, found the dimensions and I think it's the right part number and that someone just put them into the wrong box.
They're supposed to be 255 diameter, 20.4 wide and 75.1 tall.

Ideas?

James
 

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brakes.

front vented brake rotors from 77 BMW 320
Front wheel hubs from 82 BMW 320 with solid rotors.
Front griling brake caripers from 84 VOLVO 240
opel front wheel bearings are the same with the 82 BMW 320
You have to grind the mounting hole so you can lower caliper.
i am using these calipers at my race car with 13" wheels.
The caliper has two inlet brake lines. If you want i can take some pics
for you and i can give you the part #.

Pete
 

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'77 BMW 320i rotors and calipers update!!

Just realized that my former Yahoo 'classicopels' link referenced earlier in this thread is no longer functional, so I'll post the referenced pic with all the part numbers here and have also updated Keith's #4 post in this thread:

 
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