New Master Cylinder & Booster

[passthebuck]

Hey all. I havnt been doing a lot on my truck lately because training to go overseas & the birth of my daughter 2 weeks ago has kept me pretty occupied. However, this morning I installed my new mastercylinder/booster combo. It's the start of a disc conversion on the green 67. I had the mc powdercoated to avoid the look of rusty cast iron. I will eventually be putting stainless lines on the truck when $ allows. For now, I just adapted the factory lines. What ya think? More pics to follow...

[72BlckButy]

Looking good so far.

Quick question... how did you get the MC powdercoated? I thought I recalled someone saying it either couldn't be done, or that they hated to tear apart a brand new MC to PC.

[Mark B]

A like your post because I have the same project planned for my truck. Is your's all drums? Did you have to drill a new hole in the brake pedal to mount the rod in a different location than stock (I have seen this in some brake retailer instructions). How is the brake perfornance now? Did you have to buy new steel lines or can the old ones just be rebent to fit the new set up? More pics and inforrmation please!!! How many hours work do get it all done?

thanks
Mark

[Sammy]

Likewise interested in how you powder coated the MC. And wondering if it will standup to brake fluid in a month..

[mclairmo]

Looks awesome. I usually just spray my master cylinders with that cast iron grey paint you can get at most auto parts stores but powdercoating seems better. Make sure you bench bleed that master cylinder and get all the air bubbles out. I always have a hard time getting all the bubbles out.

[passthebuck]

Opening up the mc is pretty much the easiest disassembly I've ever done. All you need do is remove the internal snap ring at the end of the mc & it all comes out as a series of springs & seals that are put together into 2 sub assemblies. Snap ring pliers are cheap at Princess Auto (There are internal & external – make sure you get the right one!). Just remember the orientation & the order & it all just drops back into the bore with a splash of brake fluid as assembly lube. I made sure to have power coat guy not coat the bore, the seats or the inside of the mc. I flushed the mc numerous times with solvent & an airgun to ensure cleanliness. The powder coater told me that there are many types of powder coat & that this type is impervious to brake fluid. I put brake fluid on it the other day for reassembly & it’s still like new.

Here’s photos I took so I would remember the order of reassembly. The third photo is of the previous (crusty!) drum/drum mastercylinder.

[passthebuck]

Mark B:
My 67 was all manual drums, but this swap combined with some drop spindles & 5 bolt discs will make it a great stopper & enable me to get the wheels I want. There was no drilling required. All I had to do was unthread the old brake pushrod & thread in the new one, making sure not to preload the booster/mc. It's essentially a factory powerbrake conversion. I'm waiting on the conversion brake hoses from ECE so I havnt driven it yet. You can easily rebend the factory lines to make the hookups. I used a cheapie tubing bender to straighten sa factory bend & put another few bends in them. You will need an adaptor or two. My parts guy deals with these guys:

http://www.fairviewfittings.com/product.html?id=1692

I ordered a "DUAL MASTER CYLINDER ADAPTER" but I cant remember the size offhand. I'll check... Just the mc/booster took 1.5hr.

[72BlckButy]

Looks like we need to get Tx Firefighter (Kevin) to chime in, but I think he will be away from the board for alittle while.

Any other reviews concerning PC'ing your MC?

[TonyJohnson]

I don't see what it would hurt if you take the guts out before baking it. I sure wish I'd have at least painted mine before putting it in. Unreal how fast they rust...

[passthebuck]

Update:

I installed the lowering spindles & all the associated parts. I had to use the conversion hoses from ECE & the spindles are the specific 67-70 ones so that I didnt need to change my balljoints (I rebuilt my front end 500kms ago). I picked up a set of wheels from an Astrovan just to get me by until I can get some styling wheels. I cannot find however, the specific vacuum hose that runs from the manifold to the booster. Ideas? As you can see, I also need to lower the rear end at least 4". What ya think?

[72BlckButy]

Definitely looking good, nice install!

[C20-67_N_MO]

passthebuck I am the in process of doing the same conversion on my 3/4 ton. Can I ask what you have invested in this setup minus the master cylinder and power booster? The one I have is chromed so thats the only difference.

I just need to find a prop valve, spindles and all other related hardware.
What is confusing me is I email GMCPauls and they said I would need parts from the 71-87 truck front end to do this conversion?!

[72BlckButy]

Originally Posted by C20-67_N_MO

I just need to find a prop valve, spindles and all other related hardware.
What is confusing me is I email GMCPauls and they said I would need parts from the 71-87 truck front end to do this conversion?!

From your post I take it you are also doing the 5 lug swap? You can use either the '71-72 spindles or the '73-87, but the later model ball joints will be different (and cheaper).

[C20-67_N_MO]

Hey Nate.

Yes I am also doing the 5 lug 5x5 bolt pattern conversion along with the disc brake conversion.

[passthebuck]

C20-67_N_MO: You don’t HAVE to get a 71-87 front end, but it is possible option that is often debated on this site... I choose to not go that route & get just the conversion spindles (uses 67-70 ball joints, but you obviously need to install discs) because I had rebuilt my front end not long ago. They are available for 67-72 3/4 trucks as well. They reuse your stock ball joints (assuming they are good).

I also choose to not swap whole front ends because I did this conversion in my driveway with no help from my buddies. I surely would have needed help with a front end swap.

The combination valve (aka to some, proportioning valve) came with the master cylinder/booster combo, but you can get them from CPP & I think they come with the bracket.

I didn’t have to get new lines & was able to rebend the factory lines, thereby making them fit with a $3 adaptor.

Cost (minus the master cyl/booster):
Spindles 325CDN
Hoses 60USD
Calipers 20CDN each with core
Some paint, some work on the discs with a wire wheel & some cotter pins.
Throw in there some junkyard wheels to roll around on.

[72BlckButy]

passthebuck is correct... (and I failed to mention this above) if you are doing a 5 lug swap you do not have to go to a later model spindle; you can infact use a 67-70 spindle that will accomodate the disc itself.

[C20-67_N_MO]

Cool!

Thanks for the info guys!

And very nice setup you have there passthebuck.

And I agree with you.

Why swap out the entire front end when you can just piece it together with less work!!

[passthebuck]

Drove my truck into town 20km to get it aligned this morning. Passenger side tire squealed all the way & the drivers wasn’t happy either. I definately lost some rubber! Old skool alignment guy had it done right quick. Said that both wheels were toed in 2" (a massive amount I'm told) due to a slightly different casting shape on the new spindles. Aligned it feels a lot better.

The only glaring issue is the fact that the caster is right near zero & should be more like between 3.19 deg & 4.19 deg. Alignment guy said it would get back into spec when I drop the rear end at least 4". He was saying that this would cause it to not want to centre as quickly as one might want. No big deal.

Attached is my alignment sheet.

I forgot to ask him if he was the founder of the Turnbull AC's.

[cparman]

I paint all my master cylinders with POR15 factory manifold gray. Wipe master cylinder clean with thinner, let dry, use a sponge brush, and apply one coat. let dry 12 hours and apply one more. let dry 12 hours and install. The nice thing about this paint is that you can touch it up if you get brake fluid on it. Did my exhaust manifolds a year and a half ago also.

[72BlckButy]

That is clean cparman!

Thanks for the info, I'm going to copy your post over in the Prep/Paint for MC thread (here).

[passthebuck]

Forgot to mention that it stops WAY better. I have to re-train my self to be easy on the brake pedal now. I really had to lay into it to stop it fast & now a firm push stands the truck up on end!

[72BlckButy]

Glad to hear it was a good upgrade for your truck!