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Username Post: C3 Corvette Front Disk upgrade        (Topic#359458)
brickwhite 
Poster
Posts: 52
brickwhite
Loc: Missouri
Reg: 09-05-19
01-13-20 09:49 AM - Post#2784318    

I'm in the process of converting my 66 impala SS Coupe to front disks via the C3 corvette spindles and single piston calipers.




Still need the Calipers, pads, bearings etc...

Looking through the posts not many people comment on how they did their Master cylinder Setup.

I currently have 1966 standard drums with power vacuum assist on all 4 corners and plan on keeping the rear drum setup. I am Keeping my stock booster.

My plan on the Master is to upgrade to a 68/69 impala Power Disk/drum Master cylinder from Rock auto.

Somthing like this...

Rock auto part number - ACDELCO 18M1036 {#19106822, 19176594} $43.00



But does that have a built-in residual pressure valve?? Do any that you buy at the store? How do you tell?

My question that big Dave somewhat answered in this post - https://www.impalas.net/forums/13-brakes-susp ension/33153-manual-dual- master-cylinder-1965-impa la.html

MORE QUESTIONS: What about Residual valve and proportioning valves?

- What did the 69 impala use when it came factory with front disks?

I'd like to keep it factory looking even though a 66 did not come with Disks.

I see a lot of guys a show and cars and coffee use the generic valve with the given booster as seen below but is there a factory way of supplying the correct pressure to the drums?



[url]https://www.speedwaymotors.com/GM-Disc-Drum-Proporti oning-Valve-for-1-2-20-9- 16-18-Outlets,9878.html[/url]

Is this the Factory type option of disk/drum residual valve?



Which they do sell at Jegs etc... but is $40 by it self

[url]https://www.jegs.com/i/JEGS/555/631300/100 02/-1[/url]

In addition to that was there a factory Proportioning Valve?

I see the above "Generic" Valve does have proportioning but what was used in a factory car. I know the easy and cheap way would be to use the generic valve but I just wanted to know what was used in a 68-70.

I assume the Factory 68--70 B-body chevy with front disks used a different dist block too? Like below?





Trying to get all the parts I need before I rip into this...

Using a dual master wouldn't the pressure in the line be separate Front to Rear? Disk vs drum.

I understand that a 15/18lb or so residual valve is need to hold the pressure on the drum. Those individual valves can be purchased.

[url]https://www.summitracing.com/parts/wil-260-13784[/ url] is a $20 10lb valve.

Some stated that the OE type Master from the 68 car had res valve built-in, just wondering if that is true?


With these old cars people mix and match parts all the time. I can mix a 1 1/8" cardone Master cylinder with a Willwood front caliper kit. I've seen it done. I'm sure Willwood would rather you buy their Master because it's $400. Or their front disks at $900. (it may not be the safest, I understand)



If you get the calculation correct, which shouldn't be that hard, you can have a car that stops very well with parts you can get at any supplier. Wilwood, Baer, AC delco, cardone, etc.



I was just trying to see what others have done and if they used a C3 corvette front brakes on their Impala because that's what I'm going to use.


  • Quote:
The 1967-'69 four piston brakes on the Impala required a special steering knuckle and a special hat to hold the wheel bearings (different size than stock bearings) that are not reproduced or offered as a service part. Everything else is offered as they are reproduced as a Corvette part.



Yep, this is why I'm using the C3 corvette spindle with my impala steering arm (have to cut the stop).



Here is the mess of brake lines and proportioning valves I have to work it... I'll get it sorted.

But as for the C3 brakes. This is what I'm using. Above you saw what I found on Ebay and now it's cleaned up with new paint and bearings.



couple odd one off things...

The biggest problem I've faced so far is the Castle nut for the C3 spindle... I think it is a 27/32" nut but I haven't been able to confirm. I bought a 3/4-20 castle nut but that is too small. The corvette part sites do not give specs on the ones they sell. But 63-68 corvettes used a different spindle than the 69-82 vette. The local FLAPS did not have them nor did they want to look... Dying breed. Napa and Orielly...

The large bolt that holds the caliper bracket and shield to the spindle in the middle circled in RED it a special buy item that did not come with my spindle.

[url]https://www.zip-corvette.com/65-82-front-spindle-d ust-shield-upper-mount-bo lts.html[/url] ($15 + shipping)

-Also you will need 4 the caliper bolts with lock washers (7/16"-20 x 1.25")

The steering arms (circled in orange) will work from your impala but will need to be altered to fit the disk caliper bracket. Either cut the nub off the arm (orange line )or grind on the caliper bracket.

- dust shield gasket $10

- Dust shield $30 each if you want dust shields go mine off Ebay, there are 2 different ones but they fit the same. One is gold one (76-82) is silver (69-75) that is the only difference.
[url]https://www.zip-corvette.com/65-76-front-spindle-d ust-shield.html[/url]

I went for the re-sleeved lip seal C3 4 pistion calipers. They were about $120 each with the core charge. I know people say to find the single piston caliper but they are hard to find.

- Pads

- bearings, bearing seal

- new wheel studs

mock up.









not sure but the brake line maybe too short...that's full extension



The 4 pot calipers look good though...







 


jduffett 
Newbie
Posts: 27

Loc: Hamilton Ontario
Reg: 05-21-17
01-13-20 05:40 PM - Post#2784354    
    In response to brickwhite

  • brickwhite Said:
The biggest problem I've faced so far is the Castle nut for the C3 spindle... I think it is a 27/32" nut but I haven't been able to confirm. I bought a 3/4-20 castle nut but that is too small. The corvette part sites do not give specs on the ones they sell. But 63-68 corvettes used a different spindle than the 69-82 vette. The local FLAPS did not have them nor did they want to look... Dying breed. Napa and Orielly...


Hi Ted, I ran into the spindle nut issue too! I bought a set of refurbed C3 spindles on eBay, and they didn't come with nuts. I didn't even think about it until I went to install the old nuts and they didn't fit! Stands to reason though, that the bigger bearing gets a bigger thread. They are indeed 27/32-20. I couldn't find anyone that stocked them locally - I guess when the install torque is low and they live a cushy life covered in grease, no one ever has to replace them! That size was also used on heavy-duty full size trucks up til at least the late 90s, so you should be able to source from a GM dealer, or look for Dorman p/n 05110.

John
66 Impala SS


 
mjc1 
Senior Member
Posts: 1567
mjc1
Loc: Burlington Ontario Canada
Reg: 09-15-04
01-14-20 07:41 AM - Post#2784375    
    In response to jduffett

Nice job on the conversion so far. Nice detailing! Impressive.

As far as a master, on my 4 piston disc/drum setup I originally went with an iron Delco Moraine type master with a 1 1/8 bore, disc/disc as from a C3 Corvette. In the rear circuit, used a Wilwood 2 lb residual valve along with an adjustable metering valve. No proportioning valve. Critically, spent the time to ensure the pushrod was exactly the right length.
Brakes initially worked very good after break in, then some tuning with the valve, although it was requiring what I felt was just too much pedal pressure to be effective. Booster was the stock 11"? Delco Morain type that was in good working order, and engine vac was 15".
To get a better pedal, I went and switched over to a 1" bore master. Used a Summit branded aluminum Wilwood knock off. Good move - the result was an improved pedal feel. More travel for the same pressure, with an easier feel.I also liked that the new master came powder coated black.
I think the Disc/Drum masters will have an residual valve insert in the rear line output. Should be visible, and is removable as far as I know.
Cheers and good luck.

Summit master here.
First attempt with the Delco Moraine Master.


1967 Grande Parisienne 4DR HT
My Flickr page



 
sz0k30 
"11th Year" Gold Supporting Member
Posts: 448
sz0k30
Loc: Oakland Co., Michigan
Reg: 10-12-08
01-14-20 08:53 AM - Post#2784378    
    In response to mjc1

I did the same thing on my 67 Impala last year. I did Global West control arms, coilovers and added hydroboost. I replaced the distribution block on the frame rail with a proportioning valve and made it to mount in approx the same position.

Attachment: P1050715.JPG (611.57 KB) 1 View(s)




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brickwhite 
Poster
Posts: 52
brickwhite
Loc: Missouri
Reg: 09-05-19
01-18-20 08:54 PM - Post#2784629    
    In response to sz0k30

but the big question.... will the caliper clear my 15x8 steel wheels???
Wheel Vintiques 62 Series
Backspacing (in):4.250 in.
Offset:-6.00mm


NOPE!

I'll need to order custom backspacing or .5" spacers and longer studs.


thanks John!
I found the correct Spindle nut for a C3 spindle.

It is a 27/32" x 20. Dorman part number - 05110

If anyone goes down this road and needs it.

I had to search quite a bit to find the size and none of the parts store guys knew what I was talking about nor would look.





As for MC/res valve...

  • 67SS;227702 Said:
[FONT="Arial"]You don't need the residual valve as the most disc/drum M/C's have one inside the port for rear brakes. This is why all conversion kits do not have a residual valve included.

Disc brakes do not use residual valve, there will be one on drum brakes to reduce the reaction time for shoes to meet the drum. On disc brakes there is nothing to retract the piston and the pads are always in contact with the rotor. On drums, the shoes are self energizing which means the shoes are semi floating and when applied they wedge themselves into the drum to assist in braking. The shoes have heavy springs to pull them away when not engaged so they won't engage if slightly dragging. The residual check valve keeps some hydraulic pressure applied to keep the shoes slightly in contact but not engaged.[/FONT]




Which DISK/DRUM Master Cylinder should I purchase then?

Most of the parts places I've talked to don't know what they are talking about and the details on online part retailers don't necessarily say.

How do I know which MC is for DISK/DRUM?

Some people say that if it has a large front and small rear Reservoir the its for disk/drum.

like this

WAGNER MC101254 {#19176488, F101254, J8126739} Info
1-1/8" Bore; Vacuum Boost



Or if you go to summit MCs for a late 60s Chevy should work....



What about Bore? Should I go 1" bore or 1 1/8"??

I just want to buy what's going to work the first time...with decent pedal feel. I still need to look at my booster and old MC to see how long the push rod is.

As for what I ordered....



But this is what Came in via UPS...





I think it should work with disk/drum.... ????

Has the deep pocket like I need.

Seems my old MC was leaking anyway.







Ted


Edited by brickwhite on 01-18-20 09:02 PM. Reason for edit: No reason given.

 
mjc1 
Senior Member
Posts: 1567
mjc1
Loc: Burlington Ontario Canada
Reg: 09-15-04
01-19-20 08:27 AM - Post#2784652    
    In response to sz0k30

"How do I know which MC is for DISK/DRUM?"

A built in spring loaded residual valve will be set in place behind the tube seat. You should be able to feel it by inserting a small drill bit in the hole. You'll feel the check valve and spring resistance. Web picture as a general example of the valve,




As for your pushrod. Don't take it for granted that it'll be the correct length. You have to measure. Any extra length, even a couple of thou. could cause brake drag. It must be just very slightly undersize to be right. I know this from experience, thinking I was fine when I went through the same process as you, and I wasn't. But it was easy to figure out, and I simply ground the rod to the right length, rounding the end. Cheers.

1967 Grande Parisienne 4DR HT
My Flickr page



 
65_Impala 
Very Senior Member
Posts: 4376

Reg: 12-29-02
01-19-20 04:50 PM - Post#2784686    
    In response to brickwhite

That master looks like a drum/drum master.

I can't recommend a master besides full-size 67-69 disk brake equipped cars. I used a newer S10 aluminum master.


  • brickwhite Said:






That block on the frame isn't needed. Both front lines go right to the combination valve. If you want to hide it, put the combination valve down by the frame instead of under the master.

I ran a bolt through the bottom hole on my combination valve into the empty ear on the steering box. Not sure anymore, think I had to put a smaller bolt with a nut on the other side of the ear.



 
65_Impala 
Very Senior Member
Posts: 4376

Reg: 12-29-02
01-19-20 04:59 PM - Post#2784687    
    In response to brickwhite

Also, make sure you put a dial indicator on the rotors and shim them as close to zero runout as you can get. It's needed to have the C3 brakes work properly.



 
brickwhite 
Poster
Posts: 52
brickwhite
Loc: Missouri
Reg: 09-05-19
01-20-20 09:13 AM - Post#2784722    
    In response to 65_Impala

thanks for the info guys.

That MC has no valve.

I think I have the lines figured out.



Ted


 
brickwhite 
Poster
Posts: 52
brickwhite
Loc: Missouri
Reg: 09-05-19
01-20-20 11:11 AM - Post#2784733    
    In response to 65_Impala

  • 65_Impala Said:
Also, make sure you put a dial indicator on the rotors and shim them as close to zero runout as you can get. It's needed to have the C3 brakes work properly.



Would I shim the rotor or caliper?

What did you use?

I found the shim

https://www.summitracing.com/parts/agb-ba80303

I Found a video.

https://www.youtube.com/watch?v=I5Mj_G5LIz8

Ted


Edited by brickwhite on 01-23-20 06:28 AM. Reason for edit: No reason given.

 
65_Impala 
Very Senior Member
Posts: 4376

Reg: 12-29-02
01-22-20 06:42 PM - Post#2784922    
    In response to brickwhite

Didn't watch the video, but you shim the rotor.



 


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