Calling Paul @ Hydratech

[67ragtp]

Paul,

Got a couple questions, what size threads are in the booster where the master cylinder mounts? Thats an unusual size and pitch Im guessing 11mm x1.5 pitch, please confirm, had trouble finding a bolt at the local auto parts store.

I recieved my system with two 3/8-16 long cap screws in the threaded bores mentioned above, are these the prefered hardware to mount the master? Seems a bit sloppy in there since you can spin the master back and forth in the larger bores(using a 1-1/8 wilwood master).

The last one I ordered from you, for a first gen camaro was a 3021/3023 , this one is a cp3014 is this correct for a first gen camaro, it almost looks identicle to the one in my 67 camaro, the A-body instructions inside the info packet is prompting me to question it.

Thanks Rich

[Hydratech®]

The holes in the casting you are referring to are complete OEM oddballs at 7/16 LEFT HAND THREAD, which is why we supply these brake assist systems with the $$$ upscale chromed fasteners and stainless washers that we do. The Wilwood 260 series MC has slotted MC mounting holes to allow for both the GM 3.400~ spacing and also the Ford / Mopar 3.250~ stud spacing + a little bit of general slop in the slotted mounting holes to accomodate a WIDE variety of possible installations. After all is said and done, there is one more factor: the keyway cast into these brake assist units is somewhat less than accurate (as it is cast in), and even though we have a system that aligns the firewall mounting plate in relation to the MC mounting, sometimes having a bit of slop in the MC mounting allows the end user / installer to visually align the MC as desired to nail a perfect installed visual.

As far as the 3014 / GM A body designation? Relax in the notion that you have the correct wares. So what's the deal? CPP has streamlined their inventory to reflect the fact that the only fundamental difference between the '64-'72 GM A body and the '67-'69 GM F body ('68-'74 X body also) brake assist systems is REAR STEER vs FRONT STEER. ??? The F/X body had the steering gear box behind the rear wheels closer to the firewall, while the A body had the steering box ahead of the front wheels closer to the core support... When we used to supply completely pre-assembled PS linesets, this was a major factor that required completely different PS line lengths. Now that we supply most all systems with 4' overlength trim to fit linesets = our system # 3013 / 3014 vs our #3021 / 3023 systems are actually part for part identical (aside from long MC rod vs short MC rod specs). If you were to strike the actual vehicle designation in the installation instructions, you will also find that each step is also identical (even though the steering gear box locations vary from body style to body style).



info at hydratechbraking dot com

[67ragtp]

Paul,

Thankyou for the detailed explination, as usual it is a pleasure dealing with you. Laying the master in the booster it appears the booster is set up for a shallow master cylinder, and I will need to install the supplied slug that came with the master cylinder.

Thanks Again Rich

[Hydratech®]

Yes, you will insert the Wilwood supplied spacer bullet into the deep MC pushrod hole for use with the later design GM short MC pushrod configuration (which the CP3014 is setup for)(the CP3013 would not need to use this spacer bullet as it is the early spec long pushrod, for which the Wilwood 260 series MC is an out of the box plug n play).

ADVANCED TECH: We have observed that this Wilwood MC pushrod slug or spacer bullet has some mild innaccuracy to it from MC to MC, so double check that there is no MC piston preload by sliding this bullet into the MC, then placing the MC up against the face of the hydraulic brake assist unit. You should then experience a perfect MC casting to brake assist casting fit without any preload - if the MC seems to be floating off of the face of the brake unit casting (to where it would seem like you would want to draw the MC snug to the face of the brake unit by tightening down the MC mounting bolts), you should first double check that you do not have the brake pedal rod adjusted up to aggressively under the dash (back it off some if in doubt or disconnect the clevis at the brake pedal temporarily). If you still have the MC floating off of the face of the brake unit casting, coax the Wilwood spacer bullet back out of the MC (compressed air works well) and then grind the end of the spacer slug a few thou at a time and recheck. Continue to buzz the slug until you are confident that you have acheived a +/- .010" MC pushrod interface - essentially sneek right up to the point where you have just eliminated any MC piston preload when bolted up to the face of the hydraulic brake assist unit. If you had to err in either direction, you would be better off to have a slight air gap between the tip of the MC pushrod and the spacer slug - try to keep this at a .025" MAX. You can use some white lithium grease or suitable other material to see if / how the two interface for clearance (Plastigauge is going a bit into the splitting of hairs that isn't truly necessary). What we are really looking to do here is to insure that the MC pistons are allowed to go into a full definite state of release when the brakes are not applied. Excessive MC piston preload can cause delayed brake release in borderline cases, full on brake lockup when hot in sever cases (due to brake fluid thermal expansion just like engine coolant).

Note that the Wilwood 260 series MC's are essentially C3 Vette MC's by design (though of course much lighter and better looking):
Front port = front brakes / Rear port = rear brakes

This is good to know, as if you were out on the HRPT or elsewhere and this Wilwood MC was suspected of failure, you could pop in to a local autoparts store and source a shallow MC pushrod hole '77-'82 C3 Vette MC as a direct plug n play swap out for the Wilwood 260-8556P (with spacer bullet). If you are running the Wilwood 260-8556P without the spacer bullet on a long MC pushrod booster, note that the '68-'76 C3 Vette MC with the deep MC pushrod hole would be the unit to source...

[67ragtp]

Paul,

Thanks again for the additional info, since Im building the car from the ground up, Ive had the liberty of fitting/rebushing the pedal assy on the bench. And bolting the hydroboost and master in place. Everything is fitting up nicely, no problem with the fit of the master to booster flange(s) with the bullet in place. Also gave me an opportunity to mock up a bracket and small line for the adjustable proportioning valve. Thanks again for all the great tech! - Rich