Re: 70 5 lug disc brake thread
 

In 1970 Impala's were offered in either drum brakes (standard) or front disc (optional), they use the same size/bolt pattern studs as the trucks. It's my guess that this is why the GM book states '70 disc and '71-'72 all. Are we sure the book is only for trucks?

Re: 70 5 lug disc brake thread
 

Excellent point.

Re: 70 5 lug disc brake thread
 

Guys I called my buddy at the dealership this morning and he is going to do some indebted research on this and told me to call him in the morning. He has access to all of his old parts manuals from the 60's and 70's. He said that he would try and do some research and give me some data tomorrow. Do not shoot me yet fellows, I have one more night of 12's and then I will be off for 7 days to take a look at my truck.


PT

Re: 70 5 lug disc brake thread
 

The 70 Impala bolt circle was 5 X 4-3/4, for disc and drum. Pickups were 5X5.

Disc brakes were an option for Impala's starting in 1967.

These were the 4 piston Corvette style calipers, and used them into 1968. Sometime in 1968 they changed to the single piston calipers, that was used through 1970

The single piston caliper disc setup was an option from mid 68 through1970. The 1965-1970 Impla'a were built on the same platform.
71-76 used a different platform. AND the 71-76 used the same rotors as the 1/2 pickups, 5X5 pattern...

I'm not trying to start an arguement, I had a 67 Impala, put disc setup on it from a 1970 Impala.
The 71-76 Impala's were entirely different cars.

65-70 were rear steer, all 4-3/4 bolt circle (drum OR disc)

71-76 were front steer 5x5 pattern, ALL 71-76 were disc, NO drums on front

PT, your research will show all this!!!

Re: 70 5 lug disc brake thread
 

To all, Sorry for the snap. Had a bad day. Just had back surgery 2 weeks ago and I am still a little out of sorts. It's not an excuse just an explanation. I agree that is it possible that it was an option. Will watch quietly from my corner. :beers:

Re: 70 5 lug disc brake thread
 

Email communication can have the emotional twist, that each receiver of such can take, any direction.....Yee Ha!!!


Only one was perfect, his birthday is Sunday!!!

Re: 70 5 lug disc brake thread
 

Very well said 68Gold/white. No feelings hurt here. Hope you get that back to feeling better.


PT

Re: 70 5 lug disc brake thread
 

I perceived no ill will towards me. I'm just trying to help.. :)

I worked in an auto parts store for 13 years, now I do truck stuff. I worked for an independent auto parts store, not a chain. We did a lot of business, I learned a lot. Also learned a lot from working on m own stuff, sometimes helping a customer after quitting time....

GM usually did things that made sense, and looking at most of their parts, the parts were usually engineered to do the job.
HOWEVER 11X2 shoes on the front of a half ton pickup from 1960 till 1970 was a very poor deal.

I know I've sold parts for some 1970 C-10's w/ disc, not many...

Ford had so many stinking better ideas, it was difficult to keep up with. Going with a completely different part in the middle of the year, is insane. AND neither part usually performed the job very well. You'd of thought the later part was a major improvement, NOT.

This Ford rant is a generalization. They did this kind of thing w/ all kinds/types of parts. It wasn't something that happened every day, but you usually didn't have the info to tell where you were in relation to the stop/start date.........

Re: 70 5 lug disc brake thread
 

I have been working on these trucks since they were new and I have never seen a 70 with disc, not to mean that there were never any built. I did some research, though, and Napa does not list disc for a 70, but O'Reilleys does!!

Re: 70 5 lug disc brake thread
 

That's why in a earlier post I mentioned aftermarket parts sources as possibly being a less believeable source than O.E.
Every time we switched makes of a particular type of parts, I wouldn't let go of the old catalogs, if possible.

It's really a gas to walk in a parts store these days and ask for a part. The young person behind the counter asks all the questions the computer generates.........
Like on a front wheel car, if it has a TH400 trans....LOL...LOL

When the chains started showing up. We'd call them, ask something like..."Do you have a brass magnet, and how much???? :D

Re: 70 5 lug disc brake thread
 

Yes,GM uses a separate catalog for trucks. This comes from the 46-72 Chevrolet Truck Parts Catalog. We know there are exceptions. But,what is odd here is there is a parts listing. Generally with any exception you won't find that,due to the unique nature. If a part was borrowed from another vehicle then that is where the part number will take you.

Re: 70 5 lug disc brake thread
 

I was looking at my 46-72 catalog last night and it had the 72 plastic door panels listed as "71-72" so perhaps the catalog had its gaps or all changes didn't coincide with the model year? I realize your point it that the parts listing only adds credibility and I agree with that, guess the point i'm making is that there is no way to know for sure unless the build sheet or date code is found and I think that is what you're saying too?

Re: 70 5 lug disc brake thread
 

factory books aren't always right.... Tim's 4 speed highlander was a good example, but a more common example was the books saying no 3.07 gear limited slip rears in 67 - 72 trucks. Yet there's been about eleventy billion SPIDS shown here.
Parts stores listings are not good reference IMO... NAPA shows that big blocks were not avalible in a 72 burb... but they show it for a 1/2 ton burb. Most all parts stores don't show a 305 nor 351 V6 in GMC trucks.

71/72 SPIDs do not show disks. The SPID only shows an option, not a standard/base equipment item.

While I have been proven wrong time and time again on here (and I could be wrong on this) I'm pretty sure there were no 5 lug discs in 70. If it was an option, they would have advertised it. It would have been more common too.
Anotherr answer to this oddity is that it was swapped out many many years ago and someone forgot. There's a member on here with a 2 owner 71/72 GMC with a 68/70 grill. He swore up and down it was original and that's how his dad got it (first owner). It had been wrecked way back in the day and the body shop put the older style grill on it. His dad still said no way, it was the same style grill, and he finally showed his dad old family photos showing the truck with the correct grill. The timeline typed out on this truck in question here, the second owner, the one who painted it, may well have forgotten to mention this modification.

I'm just finding it a tough one to swallow, hardly anyone has heard of this for 40 plus years and here it is. I personally think this one is like the small window '68, and the 'ss' trucks you always hear about... and the 'special ordered vette motor'.

Re: 70 5 lug disc brake thread
 

Ok, I thought that the '70 Impala's were 5x5, but I guess I was thinking '71 and up, because I used to see truck rallys on them all the time. But I have to agree, that with tens of thousands of members on here, if it was true that discs were available in '70 on a truck, somebody would have come up with some difinitive proof by now. I've been a naysayer of other threads on here before, but I've also been around these trucks for better than 20 years. Not saying I have seen it all, but have seen alot and without a build sheet or a SPID (which now days are fairly easily reproduced) I'm going to stand my ground, after all I'm from Missouri, the "show-me state".

Re: 70 5 lug disc brake thread
 

Thanks for clearing this up for me Longhorn. I always wondered about the SPID. I have a 1970 with a "396" on my SPID but I know from research it's actually a 402. GM has done some crazy things on these trucks.
Anyone out there have a 1970 SPID showing disc brakes?

Re: 70 5 lug disc brake thread
 

Mike,
There used to be a guy in Oklahoma City that dealt in Chevrolet pickup parts, his name was Steve Davis, I believe his Company was Steve Davis Pickup Parts. It's been a long time. Ever hear of him???

Re: 70 5 lug disc brake thread
 

The name sounds familiar but I don't know that I have ever dealt with him?
Is THIS the same guy?

Re: 70 5 lug disc brake thread
 

i remember that guy back in the middle 80s he had some nice trucks (used to try and look him up when we would go down there ) lot of 67-72 bought a swb plain jane orig black paint truck from him just had used vehicles at that time

Re: 70 5 lug disc brake thread
 

Yeah,Steve Davis of Cashion Place in OKC

Re: 70 5 lug disc brake thread
 

Any updates on this thread?

Re: 70 5 lug disc brake thread
 

Keith I am waiting on my buddy to get me the copies of the paper work and I have been out of town for the holidays and had a death in the family. I have not been able to do anything and on top of that I found water in my oil on my 94 swb daily driver today. I am going to get to the bottom of it as soon as I get a chance. It has been one train wreck after another around here lately.


Thanks PT

Re: 70 5 lug disc brake thread
 

Ok guys I got some info from my buddy and have several sheets of paper out of his parts book. I am going to attach the one that has the part # on it. I also know that the rear end has a part # on it and if it is like my 70 Nova it will be on the axle tube. Does anyone know what side of the tube (top or bottom). As soon as some of this rain clears out I am going to check the rear end and I know there is a difference in width from 70-71 or around that time frame. Does any know the measurements on the two different widths from backing plate to backing plate this may also help me get to the bottom of this.


Thanks PT

Re: 70 5 lug disc brake thread
 

Backing plate to backing plate on the 67-69 was 55-1/2"
71-72 trucks width was 57".

The 1970 model year could have had either width,... but 6-lug only.
(from the factory)
This rearend is the only 67-70 rearend that will allow the use of 71-72 5-lug axles.

Re: 70 5 lug disc brake thread
 

Keith I understand on the widths and you put 6 lug only. This is part of the puzzle that I am trying to figure out on my truck. If it did indeed come with 5 lug disc then the rear end would also be 5 lug not 6 lug. I will try and get to it this week. Someone also replied about the key to telling weather or not the front had been swapped out with 71-72 spindles. If someone could tell me what a dead giveaway to telling this would be then I will try and look at that also.


Thanks PT

Re: 70 5 lug disc brake thread
 

Can you post pics of the front suspension?
I would be interested in seeing where the steel lines are routed to.
(in front of the crossmember or behind it)
And what type of rubber brake hose it has,
Also backing plate pics would be great.
The a-arms woulrd be a dead give-away if they are rubber bushed.