Another proportioning valve question

[Square_78]

Ok here's the story. I have a 1970 gmc with drum drum. I have a complete front disc brake drop spindle kit from CPP with master and booster and adj proportioning valve already assembled as one unit. I also have 4 new ball joints and tie rod ends to install. I don't have my own shop so I need to do this in two stages. I can only use my friends shop on Sundays and I don't see myself being able to do it all in one day. Is it possible for me to install my new booster and master and disc/drum proportioning valve package and run it on the existing drum drum brakes for a couple days back and forth to the shop? Could I just open up the adjustable prop valve so its running equal pressure. I just don't think I can install everything in one day. Reason is I am using my buddy's shop and can only work on Sundays. I figure if I do the booster and master and prop valve and any new brake lines one day and then I can do the balljoints, spindles and tie rods and install the discs and calipers the next Sunday? I can't leave the truck at the shop either. I have to be able to take it back to my place until the next weekend. Ya it's inconvenient but its all I've got to work with.

Will the cpp disc/drum master and prop valve work with my drum/drum brakes temporarily?

This is frustrating the hell out of my trying to figure out How to get this all done

Cheers
Lonnie.
Posted via Mobile Device

[Square_78]

This is the CPP master cylinder unit that I have to install. Comes pre assembled like this pic. I was told all this stuff with he new ball joints and tie rods will take about 10 hours to install. That's why I'm planning on two days with me doing it.
Posted via Mobile Device
Posted via Mobile Device

[lolife99]

That looks like a standard prop valve for disc/drum trucks.
I would like to say yes you can,... by my answer is no.

I really think it's going to take longer than you think.
Do the suspension first or the brake booster first,... but don't drive it until you have everything done.

I would find a different place to work, or do it in your driveway.

[Square_78]

Not really the answer I wanted to hear but I know you are right. I guess I'll just have to wait. I can't do it at home. I live in a condo. No driveway and no tools there.

You think it's going to take MORE than 2 days???

Posted via Mobile Device

[lolife99]

Originally Posted by Square_78

You think it's going to take MORE than 2 days???

Look around the board.
I've seen people take more than 2 days to break balljoints loose.
More than 2 days to bleed brakes.
You will have to bleed all 4 wheels.
Those rear brake bleeders like to break off, requiring new wheel cylinders.
Wrong parts sent.
Fabricate a longer brake pedal push rod.
Millions of possible delays.

I spent 4 hours one day just bending brake lines.
Do you have a tubing bender and a double flaring tool?

Probably going to have to trim the lower a-arms at the balljoint area.
That's a trial and error method.
Grind a little.
Install wheels.
Turn left and right.
Remove wheels.
Grind a little more.

Painting anything?
Calipers, brake rotors, tie rods, M/C?
Otherwise they will rust in just a VERY short time.

The point is,... no sense being in a hurry.

[Square_78]

I see what you're saying. Unfortunately I don't have the luxury of taking 2 days to bleed brakes or 2 days to remove a ball joint It's a fully equipped automotive repair shop I am using on a Sunday when they are closed. I've already had the spindles and lower control arms off when I installed my air ride so I'm not worried about ball joints and I've already bled my brakes when I replaced a brake line a new months ago and it only took about 20 min. I know there are always unexpected problems. I guess I should just wait and do it later or maybe over the winter. You are right. Not a good idea to be in a rush. Thanks for the info.
Posted via Mobile Device

[CC69Rat]

Just my .02, I completely understand your situation but I wouldn't subject myself to safety issues just to get it done. I too like to paint stuff while I have it apart.. and if the balljoints are the originals it may take a while to get them out. I agree man, I'd plan at least two weekends, both Sat and Sun and still that will be a chore to get it all done.

In this case I'm thinking 'The right tool for the job' having all your tools ready will save some serious time. Doing brakes in a hurry could mean leaks and / or brake failure on the way home. I wouldn't rush it at this stage. Assuming it the GMC in your avitar that's a sweet truck man.. dont risk it.

[Sammy]

Agreed about putting your self on a time line to do this. Especially something critical for safety is not very wise. Always something comes up with a monkey wrench in the process when ur on a time line to get finished quickly. Bleeding a fresh complete system could take 4 or 5 hrs some even like to open the bleeders n let them gravity bleed overnight after difficulty bleeding the entire system like this. Bottom line much better to not put yourself on a time restraint.

[Square_78]

You guys are making this job sound like a nightmare. Lol. If it wasn't for the need to get the drop spindles installed, I would never bother updating to discs. Ugggh.
Posted via Mobile Device

[70-K5]

Can you start Saturday night when the shop closes? You're then left with all day Sunday.
If it is a shop then they have space to park customer cars right? If the unexpected happens you could park it and then finish up on Monday night right? Or pay shop rates to finish during the day...

If you plan everything out and test fit parts as you can then you can eliminate issues and delays. Brake lines for instance, they are different from disc vs, drums right? I know they are for 4wd 70 K5's.

[magwakeenercew2jh]

Originally Posted by Square_78

You guys are making this job sound like a nightmare. Lol. If it wasn't for the need to get the drop spindles installed,
I would never bother updating to discs. Ugggh.
Posted via Mobile Device

Here's where you are smarter than a lot of us:

1) You are asking opinions...Great first step;
2) You are planning...Even *better* first step.


For my personal point of view, based upon a couple of frame-off builds, there are enough roadblocks to a build, project, or task that come up as surprises
that turn something that's supposed to be fun into a "nightmare" without addressing any part of the project as a "full court press"..

From my experience, most every "job" takes more time than any of us would think...Unless we build with our checkbooks (NTTAWWT). Then it usually takes
the time we figured it would *squared*.

A good place to work, reasonable tools, the right parts, and an extra stash of time, along with patience and some extra bucks, all combine to make this
a hobby instead of work.

Take any of these out of the equation? BTDT. It can get ugly. At least it has for me until I refill any of these pots.

[volksworld]

I too am affirm believer in murphy's law... that being said....when I put the 75 disc front end in my 70 I left the original drum brake master and proportioning valve in it ...and drove it that way for over 10 yrs...I had converted it to a tow truck and it was my daily driver and it stopped fine...it wasn't until I did the resto that I put in the correct master/prop valve...a disc and drum master have the same bore,the only difference is the size of the reservoir cause calipers have more volume and can run the drum reservoir dry when the pads are shot...and your prop valve is adjustable....I see no reason why this cant be driven temporarilly

[JointTech]

replacing the suspension parts on mine took me a solid 2 days.
Same with brakes. I dont know what a full shop would have that I dont other than the lift.
the suspension was a real pain in the butt. Upper balljoints took me 4 hours at least. Lowers werent easy.

that said I'd probably go for. no guts no glory.

[Longhorn 70]

I already had power brakes so I did the spindle/suspension first and drove with the OLD master cylinder on there....the first 10 or so stops were more like coasts not stops.

Then the pads seatd better and stops were stops. I then did Master and prop valve and now my stops are STOPS!

I planned 2 hours for each spindle replacement then 1 hour for both rotors and such with 1 hour to power bleed... It turned out 4 hours for one spindle 1:30 for the other and 2 hours of rotor/bleeding.

BEST of luck on this buddy.