1963-1967 Small Block Power Steering Pump Mounting Supports

[David L.]

Attached are 2 photos of 4 small block power steering pump mounting supports: GM 3786871 for a 1963, GM 3852322 for an early 1964, GM 3858138 for a later 1964, and one unknown support that has the 1.90" long slot like the 1963 & early 1964 supports but is much wider.
As far as I know I do not have the GM 3874432 support for the 1965-1967 Corvettes.
Can any identify the support in the 2nd photo on the right side?
Dave

[Richard G.]

Re: 1963-1967 Small Block Power Steering Pump Mounting Supports

I have one in my hand. It came off a SB 1970 C10 truck.
It has what is possible a WEP stamped between the bolt holes.
Difficult to read with the paint.


IMG_2421.jpg

[David L.]

Re: 1963-1967 Small Block Power Steering Pump Mounting Supports

Richard,

I traced the outline of 3 of the supports.
My "unknown" support appears that it could be used inlace of the 3852322 and 3786871 supports. The 3858138 support which has a much longer slot is used as a replacement for the 3852322 and 3786871 supports but not the effective adjustment slot length is limited to about 3/4".

Do you think that your support was original equipment on 1970 C10 truck SB engine. A lot can change in 52 years.
Dave

[Timothy B.]

Re: 1963-1967 Small Block Power Steering Pump Mounting Supports

David, great post, can you explain where this "rib" is located, they all sort of look the same to me. I remember thinking something looked different on a 63 bracket.

[David L.]

Re: 1963-1967 Small Block Power Steering Pump Mounting Supports

The 3852322 and my "unknown" supports both have the 1" X 3/8" rib on the angle bent to strengthen it, I assume.

[David L.]

Re: 1963-1967 Small Block Power Steering Pump Mounting Supports

I have one in my hand. It came off a SB 1970 C10 truck.
It has what is possible a WEP stamped between the bolt holes.
Difficult to read with the paint.


[ATTACH=CONFIG]113104[/ATTACH]

My "unknown" P/S pump support has a triangle stamping on the 7/8" wide by 4 1/2" +/- section with what looks like a "3-point star" inside this triangle. I assume that this the manufacture's logo.

Also in my collection I have a 3860455 P/S pump BRACKET (that mounts on the engine block using the 2 holes spaced about 1 5/8" c/c) that has the stamping "WCF" (or maybe it is "WCP"). This 3860455 bracket is very similar to my 3786870 (1964-1964) bracket any my 3941114 (1968 Chev.) bracket. In the near future I will start a new thread about the similar P/S pump BRACKETS with photos.

[David L.]

Re: 1963-1967 Small Block Power Steering Pump Mounting Supports

Richard,
I just found another box of P/S brackets & supports in my garage attic. Another "unknown" P/S pump bracket with the same "3-point star" inside a triangle stamping and the "rib" on the angle bend. According to my tag I removed it from a "late" 1964 Chevrolet with V8 engine but with a 1962 Chevrolet 283 engine stamped "T0507D" on the front "pad" with an intake manifold casting date "E 7 62" (both dated May 7. 1962).

[Joe R.]

Re: 1963-1967 Small Block Power Steering Pump Mounting Supports

Attached are 2 photos of 4 small block power steering pump mounting supports: GM 3786871 for a 1963, GM 3852322 for an early 1964, GM 3858138 for a later 1964, and one unknown support that has the 1.90" long slot like the 1963 & early 1964 supports but is much wider.
As far as I know I do not have the GM 3874432 support for the 1965-1967 Corvettes.
Can any identify the support in the 2nd photo on the right side?
Dave

Hi Dave:

This is a very interesting post. I was not aware that GM used so many different versions for this part.

Recently I have been studying the mounting brackets for the PS pump because I'm interested in moving the pump about 1/8" rearward compared to the stock 1967 location.

I've been looking at the PS pump mounting bracket because I have a side project to put a set of deep-groove pulleys a 1967 L79 that has both factory A/C and power steering. For this particular L79 configuration, GM used the standard-groove pulley set from the 300 hp engine (long story that I have previously discussed in another thread regarding the "HP" engine assembly code).

I have three questions prompted by your post:

1) Did all of these rear supports use the exact same cradle bracket for the PS pump?

2) For each of the rear support brackets that you show, there is an offset that places the adjustment slot slightly rearward of the mounting tab for the two bolts that retain the bracket to the front of the block. Is this offset identical for all of the brackets you have?

3) Are you aware of any GM configuration of the rear bracket that used only the two bolts in the front of the block and did NOT have a third mounting point at the motor mount?


Thanks in advance for any info you can provide.

[David L.]

Re: 1963-1967 Small Block Power Steering Pump Mounting Supports

Hi Dave:

This is a very interesting post. I was not aware that GM used so many different versions for this part.

Recently I have been studying the mounting brackets for the PS pump because I'm interested in moving the pump about 1/8" rearward compared to the stock 1967 location.

I've been looking at the PS pump mounting bracket because I have a side project to put a set of deep-groove pulleys a 1967 L79 that has both factory A/C and power steering. For this particular L79 configuration, GM used the standard-groove pulley set from the 300 hp engine (long story that I have previously discussed in another thread regarding the "HP" engine assembly code).

I have three questions prompted by your post:

1) Did all of these rear supports use the exact same cradle bracket for the PS pump?

2) For each of the rear support brackets that you show, there is an offset that places the adjustment slot slightly rearward of the mounting tab for the two bolts that retain the bracket to the front of the block. Is this offset identical for all of the brackets you have?

3) Are you aware of any GM configuration of the rear bracket that used only the two bolts in the front of the block and did NOT have a third mounting point at the motor mount?


Thanks in advance for any info you can provide.

My answers to your questions for whatever they are worth:

1. No, According to the 1963-1967 Assembly Manuals the 1963-1965 Corvettes used P/S Pump Bracket # 3786870 (or cradle as you call it).
The "early" 1965 Corvettes used bracket # 3868886 which according to the REVISION RECORD was changed to # 3874426 on 11/9/64. GM # 3874426 was then replaced by GM # 3887107 as per the REVISION RECORD.
The 1966-1970 Corvettes used the 3887107 bracket.
In my collection I have a several 3786870 brackets, a NOS 3887107 bracket, and the following very similar Chevrolets brackets (or cradles as you call them): GM # 3860455 and GM # 3941114.

2. There are 2 offsets on the 3 P/S Pump Supports in my photos above (GM # 3786871, 3852322, 3858138) Each asset is about 1/8" with a total offset of about 1/4 rearward from the 2 mounting bolt holes on the block. The 1st offset is about 1/2" to 7/8" from the center of the 2 bolt holes. The 2nd offset is about 2 3/4" to about 4 1/4" from the 2 bolt holes. I have looked any photos of the 3874432 support (for 1965-1970 Corvettes) on the web and it appears to identical to my NOS 3858138 support but there must be a slight difference. Note: My "unknown" P/S rear support has just one offset of about 1/8".

3. No. I have a few P/S rear adjustment braces that have 2 bolt holes that line up with 2 of the 3 bolt holes of the engine mount bolt holes, GM brace # 3860456 for 1966-1967 Chevrolets. My 1968 Chevrolet P/S rear adjustment brace is similar except that it has 3 bolt holes that line up with the all 3 engine mount bolt holes.

BTW, My 2 "unknown" P/S rear supports MIGHT be GM # 5775580 for 1962 All models w/8 cyl. eng. as shown in the GM Chevrolet Parts Catalogue (No. 651) dated December 1964. The researching continues.
Dave

[Joe R.]

Re: 1963-1967 Small Block Power Steering Pump Mounting Supports

My answers to your questions for whatever they are worth:

1. No, According to the 1963-1967 Assembly Manuals the 1963-1965 Corvettes used P/S Pump Bracket # 3786870 (or cradle as you call it).
The "early" 1965 Corvettes used bracket # 3868886 which according to the REVISION RECORD was changed to # 3874426 on 11/9/64. GM # 3874426 was then replaced by GM # 3887107 as per the REVISION RECORD.
The 1966-1970 Corvettes used the 3887107 bracket.
In my collection I have a several 3786870 brackets, a NOS 3887107 bracket, and the following very similar Chevrolets brackets (or cradles as you call them): GM # 3860455 and GM # 3941114.

2. There are 2 offsets on the 3 P/S Pump Supports in my photos above (GM # 3786871, 3852322, 3858138) Each asset is about 1/8" with a total offset of about 1/4 rearward from the 2 mounting bolt holes on the block. The 1st offset is about 1/2" to 7/8" from the center of the 2 bolt holes. The 2nd offset is about 2 3/4" to about 4 1/4" from the 2 bolt holes. I have looked any photos of the 3874432 support (for 1965-1970 Corvettes) on the web and it appears to identical to my NOS 3858138 support but there must be a slight difference. Note: My "unknown" P/S rear support has just one offset of about 1/8".

3. No. I have a few P/S rear adjustment braces that have 2 bolt holes that line up with 2 of the 3 bolt holes of the engine mount bolt holes, GM brace # 3860456 for 1966-1967 Chevrolets. My 1968 Chevrolet P/S rear adjustment brace is similar except that it has 3 bolt holes that line up with the all 3 engine mount bolt holes.

BTW, My 2 "unknown" P/S rear supports MIGHT be GM # 5775580 for 1962 All models w/8 cyl. eng. as shown in the GM Chevrolet Parts Catalogue (No. 651) dated December 1964. The researching continues.
Dave

Thanks Dave for your detailed response. Regarding offsets, I'm referring to the overall net offset, in inches, regardless of whether it is made up of one or two separate segments. What I'm trying to understand is whether the position of the PS pump was ever more forward, or farther back, than the position used in 1967. If the position was changed, it would likely affect both the rear brace and the cradle.

I'm away from home right now, but when I get a chance, I will take a couple photos that show the dimensions I'm interested in.

My recollection is that the mounting points on the cast iron "Saginaw" pump casting were identical for a very long period of production, in the range of 1963-1980. If so, the only way that the PS pump could have been moved forward or back would be to change the offsets on the rear brace and the cradle.

[David L.]

Re: 1963-1967 Small Block Power Steering Pump Mounting Supports

Thanks Dave for your detailed response. Regarding offsets, I'm referring to the overall net offset, in inches, regardless of whether it is made up of one or two separate segments. What I'm trying to understand is whether the position of the PS pump was ever more forward, or farther back, than the position used in 1967. If the position was changed, it would likely affect both the rear brace and the cradle.

I'm away from home right now, but when I get a chance, I will take a couple photos that show the dimensions I'm interested in.

My recollection is that the mounting points on the cast iron "Saginaw" pump casting were identical for a very long period of production, in the range of 1963-1980. If so, the only way that the PS pump could have been moved forward or back would be to change the offsets on the rear brace and the cradle.

Joe,
When all 4 of my P/S rear supports as shown in my photo above are laying on a flat table with the slot side flat on the table the measurement from the table surface to the center of the single hole is 4 1/4".
Dave

[David L.]

Re: 1963-1967 Small Block Power Steering Pump Mounting Supports

Here is a photo of a P/S Pump Bracket Kit, GM # 3928493, listed for 74-82 Y in Gr. 6.606 that I bought from my local Chevrolet dealer back in the 1980's. The kit included 2 pieces: Bracket # 3887107 and Support # 3858138. This support is identical to my other NOS 3858138 support. I still do not know the difference between the 3858138 support and the 3874432 support.

[David L.]

Re: 1963-1967 Small Block Power Steering Pump Mounting Supports

Below is a photo of 6 different P/S Pump Brackets: 1963-1964 Corvette & 1963-1968 Chevrolet
From the left side to the right side of the photo:
1. Possibly early version of the 3786870 bracket with large "rib" on bottom. I have one more just like it and neither one had been modified.
2. 3786870 bracket with 1/2" did. hole on flat bottom
3. 3786870 bracket from 1964 Chevrolet 283 with flat bottom
4. 3860455 bracket from 1965 Chevrolet 283 with large "rib" on bottom
5. 3860455 bracket from 1966 Chevrolet 283 with flat bottom
6. 3941114 bracket from 1968 Chevrolet 307 with flat bottom

[Joe R.]

Re: 1963-1967 Small Block Power Steering Pump Mounting Supports

Below is a photo of 6 different P/S Pump Brackets: 1963-1964 Corvette & 1963-1968 Chevrolet
From the left side to the right side of the photo:
1. Possibly early version of the 3786870 bracket with large "rib" on bottom. I have one more just like it and neither one had been modified.
2. 3786870 bracket with 1/2" did. hole on flat bottom
3. 3786870 bracket from 1964 Chevrolet 283 with flat bottom
4. 3860455 bracket from 1965 Chevrolet 283 with large "rib" on bottom
5. 3860455 bracket from 1966 Chevrolet 283 with flat bottom
6. 3941114 bracket from 1968 Chevrolet 307 with flat bottom

Thanks Dave. This is very interesting info on all (or most) of the evolution of the power steering pump mounting cradles. It's not clear why GM kept making such small revisions in these parts. Usually, a revisions were only made to correct defects or reduce costs.

Structurally, the biggest change I see is between the 3887107 cradle that you show in post #12 compared to all the versions shown in Post #13. The 3887107 is clearly more expensive to make than all the others, but it likely provides a more rigid support for the pump.

[David L.]

Re: 1963-1967 Small Block Power Steering Pump Mounting Supports

Thanks Dave. This is very interesting info on all (or most) of the evolution of the power steering pump mounting cradles. It's not clear why GM kept making such small revisions in these parts. Usually, a revisions were only made to correct defects or reduce costs.

Structurally, the biggest change I see is between the 3887107 cradle that you show in post #12 compared to all the versions shown in Post #13. The 3887107 is clearly more expensive to make than all the others, but it likely provides a more rigid support for the pump.

All 6 of the brackets in my photo above are basically the same.
I believe the modifications were made for clearance purposes (balancers & C/S pulleys) and some are slightly different because there were made by different manufacturers.
Starting from the left side:
1. Untagged bracket has a triangle stamping with a 3-pointed star inside and a large "rib" on bottom.
2. 3786870 bracket with 1/2" hole has no stamping markings.
3. 3786870 bracket from 64 Chev. 283 has a "WCF" stamping.
4. 3860455 bracket from 65 Chev. 283 has no stamped markings but has a large "rib" on bottom.
5. 3860455 bracket from 66 Chev. 283 has a WCF" stamping with a flat bottom.
6. 3941114 bracket from 68 Chev. 307 has no stamped markings but has a flat bottom.

I have 8 more of these same brackets for a total of 14 in my collection.

There are no replacement bracket listed for the 3786870 bracket from 1965 to 1990 in any of my 6 different Chevrolet & GM Parts Parts History catalogs for service parts sold over the counter.
GM # 3860455 was replaced by GM # 3941114 in August 1968 as per Parts History.