I have a 70 w-30 Ram Air with a TH400 transmission that has a big vacuum brake booster. I have another 442 no ram air with TH 400 transmission but the guy I bought it off of who bought it off the original owner and said the original owner swore that the car was a w30 or had a w30 engine. I haven't had time to try to find a build sheet if it exists or check that the parts match. I was wondering why the difference. I thought I read somewhere that the factory w-30 cam required the non vacuum assisted brakes. But my w-30 has the vacuum assist. Thanks for any information that can explain this.

 

in 1970 an automatic optioned W30 can have power brakes, but it doesn't mean it had to have them, power disc brakes were an option as well. So I suppose you could have two automatic trans W30 cars one with power brakes one without rather easily.

 

Lots of people "swear" lots of things about their cars. Take it with a grain of salt. It's very easy to tell if the engine is a W-30. Check the casting letter and casting number on the heads. W-30s had unique heads for 1970. Also, note that unlike prior years, all W-30s got disk brakes in 1970, manual-only for the 4spd cars and power optional for the AT cars. Note that AT W-30s got a milder cam than the 4spd cars in 1970, a little-known secret. How the two engines were rated at the same HP and torque remains a mystery...

 

Unless you selected the disc brake delete option, which was was only available for a few months at the beginning of the 1970 model year. So you might find a few early-build W-30s with drums all around.

 

I'm curious to see if you have any factory documentation of this. All the factory literature I've seen shows manual disks as included in the W-30 package as the base and only shows power disks as an option. Now, since the shoes in drum brakes can be adjusted back to reduce drag, they used to be preferred for drag racing, so it isn't out of the realm of possibility, but I've never seen anything concrete about this delete option.

 

You're right that manual disc brakes were included in the W-30 (and W-31) option in 1970. But for a very short period of time you could choose to delete the discs and go with drums.

Here's my list of Factory documentation of the existence of option JL7, Disc Brake Delete, for 1970 model year W-30s and W-31s:

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1970 Salesmen's Prices, Equipment, Colors & Trims, Specifications pocket book:
-- The August 1969 edition lists on the 442 page:
"JL7 Brakes, Delete Manual Front Disc -- W30 required. Replaced by drum brakes."
-- A similar listing appears on the F-85 and Cutlass S pages, for W31.
-- On the back cover, Principal Revisions in Available Equipment:
"JL7 Brakes, Delete Manual Front Disc. Added for W Machines."

-- The January 1970 edition of this Salesmen's pocket book makes no mention of option JL7.

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70 Product Bulletin, Bulletin No. 1, Sept 26th 1969
(I believe this is a Canadian document):
"Subject: Oldsmobile Sales Handbook Changes."
-- Option Page 8: "Option JL7 Deletion of Manual Front Disc Brakes has been cancelled."

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1970 Oldsmobile Inspector's Guide, Aug. 1, 1969
-- pages 22 - 23: Accessory Codes -- 1970 Models
The copy of these pages I've seen is heavily pixelated, but it appears that Box 74 Line 1 is: "JL7, Delete Power Disc Brakes (W30, W31)"
-- page 26 is much more legible and definitely mentions option JL7.

***************************
Option JL7 does NOT appear on the Wholesale Car Order Form for 442s dated January 1970. I don't know if it appears on any earlier edition of this form.

************************************************

So it appears that there was a very small window, at least between August 1 and September 26, 1969, when you could delete the disc brakes on your W30 or W31. Of course, the next question is: what dates did the factory actually build with the deletion? If I ordered JL7 in September and the car was built in October, would I get discs or drums?

Complicating this is the fact that I'm not aware of any 1970 W-30s built before October of 1969. (They might be out there, but I haven't seen them.) So if no W-30s were built during the window that JL7 appeared on the books, were any built with it?

I'd love to hear from anyone with more information or experience in this matter.

 

Brian,

Very cool info. Thanks for taking the time to post that. I was not aware of this early model year option.

 

My pleasure. It's not like I've got a life or anything.

I should mention that my collection of 1970 factory literature is FAR from exhaustive. I bet there's other mentions of JL7 in other literature.

This whole situation serves as a good reminder that we should never say never -- and that dates matter. An organization as large as Oldsmobile is in a constant state of motion. Changes happen every day -- in Engineering, in Marketing, and on the production line. I'm often guilty myself of "proving" something by looking in, say, the assembly manual but never checking the revision history nor considering that I may not have the last issue of that page.

Now all we need is for someone to come forward with an original, early-build '70 W-30 without disc brakes.

 

Thank all of you for the posts! Work has gotten in the way of working on the car. I'll check out the car and try to find the build sheet.

Ben