1989 SUBURBAN V2500 PROJECT

[Todd McLaughlin]

Next was the clutch pedal setup, after removing the old automatic brake pedal set, I searched the US for about 4 months trying to find a hydro clutch system, to now avail I failed in my hunt. Frustrated I returned to the donor truck I found the hydro boost brake system and removed the manual pedal setup. Knowing the hydro boost came from this vehicle I had no trouble with brake pedal push rod alignment. The clutch pedal was a total different story. With some basic welding skills and a little luck this is what I came up with.

This is the brake pedal and the clutch pedal dis-assembled.



After a few re-installs I checked the clutch alignment and started the modifications, I installed the clutch master cylinder in the manual speedometer cable hole the alignment worked great.

 

[Todd McLaughlin]

Found a hitch pin at the local fasteners store for about 80 cents.

 

[Todd McLaughlin]

About 2 hours work here they are.

 

[Larry]

You're not kidding the hydro clutch pedal box is getting hard to find. I know of at least 5 guys looking for a set now. I totally lucked out a few years ago when I found mine, not only was that donor truck a hydro pedal truck it also had hydroboost. It was a '90 chassis cab but was still the old square body style.

Man, you're going to love hydroboost! Stopping power! Piss on rear disk….hydroboost is the best brake upgrade you can do.

Regarding the mounting of your master cylinder, the OEM hydro pedal box has two rods that extend from the pedal box to the firewall and become the studs for the master to mount. Without tying the master to the pedal box you run the risk of the firewall doing an oil can affect where it flexes back and forth as you step on the clutch and the rod pushes in and out. You might try to figure out a way to tie them together to prevent the firewall from cracking at the master cylinder. I saw a guy in Colorado Springs that did a total hack job NV4500 swap where he used all aftermarket goodies for the clutch. Basically, he used a dirt track race car pedal, master, slave, lines, etc. The firewall started cracking at the master because of the oil canning affect which is exactly why the factory pedals have the rods to tie them together.

This picture shows the two rods going to the firewall on my K10. My Suburban was a factory manual trans truck that already had the correct hydro pedals so I did not have to do anything to it. Again, these rods are also the mounting studs for the master.

Here is a comparo of the hydro vs. mechanical pedal boxes that also show the rods with studs on the end

 

[Todd McLaughlin]

Thanks again Larry for the heads up on the Firewall flex around the master cylinder. Ill be working on that real soon.

NV4500 TIME!!!!

Found this old dog in southern Montana but it was a poor mans hack job of a repair.

 

[Todd McLaughlin]

Next I Had a transmission guy go through the whole NV4500 and fix anything that seemed out of place or worn out, they fixed all the seals and I was ready to paint.

 

[Todd McLaughlin]

Out with the bullet proof TH400 and the NP241.

 

[Todd McLaughlin]

I installed the bell housing and started the fitment process for the floor shifter.

 

[Larry]

The paint job looks awesome! Anxious to hear how that bellhousing works out for you in a square body. The 92-94 GMT400 bellhousing in your pictures is known for causing clearance issues with the passenger’s side exhaust manifold/header and interference with the front driveshaft and there isn’t an off-the shelf hydro line that works for that combo as the 85-91 square body specific master cylinder has a different connection than the 92-94 GMT400 slave (threaded vs. push in/roll pin).

I have one of those early GM NV4500 bells as well as a 95-06 internal slave/release bearing bells laying around, but chose to use an Advance Adapters bellhousing (712576) and slave bracket (715535) on the K10 and Polar Bear Suburban, so I could use all matching period correct square body hydro matching pieces (m/c, hose & slave) for the sake of finding off the shelf replacement parts down the road or on the trail. Anxious to hear of what you have works well together with off the shelf parts without having to make a custom hydro line.

Here is a pic of the Polar Bear with the AA Bell and AA slave bracket (on drivers side) with the period correct off the shelf slave that works with the off the shelf period correct hydraulic line.

 

[underdrive]

You know, I think I just figured out why our '78 pedal lined up with the hydroboost perfect when most others have to move the pedal pin or swap pedal - our truck had manual brakes from the factory. So my theory is that to make up for the lack of vacuum assist GM used simple leverage by installing a pedal with higher mechanical advantage due to its pin being closer to the pivot. Was a stick truck too, three on the tree to be exact, not fast but still tons of fun to drive, kinda oldschool. Should have never sold it...

 

[underdrive]

Todd, what transfer case are you using with the NV4500?

 

[Todd McLaughlin]

Hey Underdrive, I decided for the time being to keep the NP241 with a slip yolk so I wouldn't have to make any drive line changes. It bolted right up without any modifications. The Plan is to get a NP205 and twin stick it like Larry's truck, but I'm having trouble finding a 32 spline unit.

 

[Todd McLaughlin]

The paint job looks awesome! Anxious to hear how that bellhousing works out for you in a square body. The 92-94 GMT400 bellhousing in your pictures is known for causing clearance issues with the passenger’s side exhaust manifold/header and interference with the front driveshaft and there isn’t an off-the shelf hydro line that works for that combo as the 85-91 square body specific master cylinder has a different connection than the 92-94 GMT400 slave (threaded vs. push in/roll pin).

I have one of those early GM NV4500 bells as well as a 95-06 internal slave/release bearing bells laying around, but chose to use an Advance Adapters bellhousing (712576) and slave bracket (715535) on the K10 and Polar Bear Suburban, so I could use all matching period correct square body hydro matching pieces (m/c, hose & slave) for the sake of finding off the shelf replacement parts down the road or on the trail. Anxious to hear of what you have works well together with off the shelf parts without having to make a custom hydro line.

Here is a pic of the Polar Bear with the AA Bell and AA slave bracket (on drivers side) with the period correct off the shelf slave that works with the off the shelf period correct hydraulic line.

Hi Larry, When I drove to get the NV4500 I collected all the parts for the clutch (master, slave and 2 or 3 sets of hoses the guy had laying around), The set up seems to work ok, I did have a little concern with the headers rubbing the bell housing but so far not a scratch. The master and slave with the hose that I used was a little hard to bleed but when installed it I can reach through the fender well and bleed the slave with plenty of room. I'm having trouble finding replacement parts so far just in case of future problems, I found a guy at my local Napa, lol between Coeurd'alene Idaho and Spokane Washington we have 9 Napa's so plenty to choose from, I showed him the hose and he is able to make me a spare with the same fittings for less that 10 dollars, so that is a score.

 

[Todd McLaughlin]

Larry do you have some pics of the Clutch Master that you used, Is the fluid bowl remote or attached?

 

[Todd McLaughlin]

Just another idea I am trying out, needed a little extra power up front.