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Old 02-07-2010, 08:09 PM   #1
chevyross
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Question 1970 Blazer disk brake conversion

I'm planning to convert my front drum brakes on my 1970 Blazer to disk brakes. What parts will I need to locate? Can I use my steering knuckles on the Dana axle? Thanks.
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Old 02-07-2010, 09:01 PM   #2
bigdon-70blazer
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Re: 1970 Blazer disk brake conversion

Good question!
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Old 02-07-2010, 10:56 PM   #3
SeventyOne
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Re: 1970 Blazer disk brake conversion

Do you have an open or closed knuckle? Can you see the axle u-joint?

If it's open, I would go to a junkyard and get the knuckles out from a 71-91 (or later even?) 1/2 ton chevy to start. It will give you the spindle, outer axle shaft (if it's different), caliper brackets, and caliper cores.

Then get a new rotor and either rebuild or replace the calipers, install new pads, new bearings.

Probably something I'm leaving out but that ought to get you close.

Last edited by SeventyOne; 02-07-2010 at 10:57 PM. Reason: spelling
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Old 02-07-2010, 11:01 PM   #4
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Re: 1970 Blazer disk brake conversion

Ok with a little research you should have a closed knuckle axle. I am not sure if it is as easy as I wrote above or if your inner knuckles will even allow an open style outer knuckle to bolt up to it. Can you post a pic?
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Old 02-08-2010, 12:40 PM   #5
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Re: 1970 Blazer disk brake conversion

Why not just replace the whole front end with one that already has disc brakes? You should be able to pick up a disc brake dana 44 front for around $75-$100 and it would be a lot easier.
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Old 02-08-2010, 01:02 PM   #6
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Re: 1970 Blazer disk brake conversion

In my 70 we went with the complete front end
My 70 had power brakes Drum/Drum on it . When we replaced the front end the brakes were soft to me. I changed the prop valve and the M/C. The fitting on the drum brake lines are different than the drums. I had to search fittings at the plumbing warehouse
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Old 02-08-2010, 01:41 PM   #7
SeventyOne
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Re: 1970 Blazer disk brake conversion

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Originally Posted by drunkbus View Post
Why not just replace the whole front end with one that already has disc brakes? You should be able to pick up a disc brake dana 44 front for around $75-$100 and it would be a lot easier.
So long as the gear ratio is the same. I would still recommend redoing the brakes and bearings - would probably cost the same. and maybe even axle seals depending on condition.

Something I read while doing some quick research was that the steering arm/outer knuckle changed in 1971 so this swap might affect the steering geometry.
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Old 02-08-2010, 03:50 PM   #8
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Re: 1970 Blazer disk brake conversion

Quote:
Originally Posted by SeventyOne View Post
Do you have an open or closed knuckle? Can you see the axle u-joint?

If it's open, I would go to a junkyard and get the knuckles out from a 71-91 (or later even?) 1/2 ton chevy to start. It will give you the spindle, outer axle shaft (if it's different), caliper brackets, and caliper cores.

Then get a new rotor and either rebuild or replace the calipers, install new pads, new bearings.

Probably something I'm leaving out but that ought to get you close.
If original yet, it should have drum brakes with an open knuckle. One year only for that. I would do as suggested and just find a donor front end from 71 up into the late 70s. I believe it is basically a bolt in procedure. Make sure the gear ratio is the same...
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Old 02-08-2010, 05:14 PM   #9
pound41
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Re: 1970 Blazer disk brake conversion

Quote:
Originally Posted by SeventyOne View Post
So long as the gear ratio is the same. I would still recommend redoing the brakes and bearings - would probably cost the same. and maybe even axle seals depending on condition.

Something I read while doing some quick research was that the steering arm/outer knuckle changed in 1971 so this swap might affect the steering geometry.
My 70 blazer is out of comission for floor pan replacement. During the short time I drove it I swore to my Dad that the steering/turning radius was different than my 71 blazer
It seemed to me that it did not turn as well in one direction. I really noticed it in turning into parking spaces etc.I will have to research that steering arm/outer knuckle change
Thanks
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Old 02-08-2010, 05:57 PM   #10
SeventyOne
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Re: 1970 Blazer disk brake conversion

Quote:
Originally Posted by pound41 View Post
My 70 blazer is out of comission for floor pan replacement. During the short time I drove it I swore to my Dad that the steering/turning radius was different than my 71 blazer
It seemed to me that it did not turn as well in one direction. I really noticed it in turning into parking spaces etc.I will have to research that steering arm/outer knuckle change
Thanks
I read that 71 was the first year for the 3 hole steering arm/knuckle. This seems to be backed up because if you buy lifts for a fist gen Blazer it should ask if you need the lifted steering arm or drop pitman.

Anyone with a stock 70 axle want to take a pic?

Last edited by SeventyOne; 02-08-2010 at 05:58 PM.
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Old 02-08-2010, 10:25 PM   #11
cvalcore
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Re: 1970 Blazer disk brake conversion

it would be ten easier just to swap the axle out you can buy them for $100 bucks all day long i no because i have had several of them and had a very hard time selling them in the past. i just gave one away not to long ago out of a 72 blazer to a guy that was doing the same thing
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Old 02-08-2010, 10:35 PM   #12
Livrat
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Re: 1970 Blazer disk brake conversion

Quote:
Originally Posted by chevyross View Post
I'm planning to convert my front drum brakes on my 1970 Blazer to disk brakes. What parts will I need to locate? Can I use my steering knuckles on the Dana axle? Thanks.
1970 Blazer is a one year only open knuckle drum brake Dana 44 front axle..
Yes you can use your existing steering knuckles,, all you need are 71 up spindles, hubs. rotors, backing plates, 71/72 disc brake master cylinder and proportioning valve and all the front brake lines.
It is easier to find a donor axle and just swap the entire assembly.. but if you cannot find one with the correct gear ratio then just swap from the spindles out..
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