Build The Clustertruck Rides Again - Refurbishing a 1975 Chevota

[RWBeringer4x4]

Last but not least, I used the same procedure I used on the front differential to remove the slop from my rear pinion, and get everything tightened back up. The rear pinion bearing makes me nervous, but I'll run it for a while and see if the play returns before I give up on it entirely.

I followed the same procedure as before, I sanded the thick washer from ~2.87mm to ~2.84mm using 400 grit sand paper, and mineral spirits as a cutting agent. This also helped to remove some of the wear marks that had formed from the washing spinning in the sloppy rear pinion. They're not entirely gone, but they're smoother...

Then, I swapped the 0.43mm thin shim that had been in there (and heavily damaged) with a fresh 0.25mm thin shim. The combination of these two things got me right into the ~11 in. lb. range I was shooting for on the first shot!

Slowly but surely plugging along! Really looking forward to getting the front axle back on-board, and hooking everything back up.

 

[RWBeringer4x4]

Built a bracket for the proportioning valve now plumbed into my rear circuit.

Fitted a cardboard pattern in the truck to "rough out" a shape that would work:

Traced it to a piece of sheet metal, then used a grinder to cut it out (and remove some excess metal). Luckily, my future-father-in-law happens to have a sheet metal brake, which allowed for some more precise bends than the usual "clamp in bench vice, wack with BFH" method.

Cleaned it up, and rounded off the sharp edges on the arbor wheel:

and last but not least, painted with Duplicolor caliper paint, and mounted. Pretty happy with how it turned out. It's not a thing of beauty, but it certainly will get the job done.

Ultimately, I'll need a slightly longer vacuum line now to reach the booster. The existing one, while in OK shape dry-rot wise, is coming up a little short trying to circumvent the bracket. I'll also probably route it over the top of the booster, and twist the input up, to keep it away from the bracket. Wouldn't want vibrations slowly cutting their way through the vacuum line...

 

[RWBeringer4x4]

I also polished the turd a little further:

These springs are ultimately destined to come out altogether, to make way for a 2.5 or 4 inch lift (someday).

That said, the transmission/clutch will have to come next, along with (most likely) patching up the hardtop and mitigating some of the bigger rust issues. As such, I decided to do a half-assed job of cleaning/coating these springs in some Rust Encapsulator. Again, no real purpose, aside from aesthetics.

In the process, I found that a large majority of my shackle/pin bolts has worked themselves loose - so I tightened everything back down. Unfortunately, it seems that one bolt on each of the front spring pins have stripped (they just spin in their holes. These are auxillary bolts (not the pin holding the spring on) and they seem to be holding, for now, but not happy to discover that...

 

[Vae Victus]

Last but not least, I used the same procedure I used on the front differential to remove the slop from my rear pinion, and get everything tightened back up. The rear pinion bearing makes me nervous, but I'll run it for a while and see if the play returns before I give up on it entirely.

I followed the same procedure as before, I sanded the thick washer from ~2.87mm to ~2.84mm using 400 grit sand paper, and mineral spirits as a cutting agent. This also helped to remove some of the wear marks that had formed from the washing spinning in the sloppy rear pinion. They're not entirely gone, but they're smoother...

Then, I swapped the 0.43mm thin shim that had been in there (and heavily damaged) with a fresh 0.25mm thin shim. The combination of these two things got me right into the ~11 in. lb. range I was shooting for on the first shot!


Slowly but surely plugging along! Really looking forward to getting the front axle back on-board, and hooking everything back up.

Nice. Will be doing this over the weekend. Heading out now to find a local torsion meter (?).

Laughed at your comment on painting over flash rust. I'm right there with you. By the way, OCD should be "CDO" ( that's in alpha order).

 

[RWBeringer4x4]

Nice. Will be doing this over the weekend. Heading out now to find a local torsion meter (?).

Laughed at your comment on painting over flash rust. I'm right there with you. By the way, OCD should be "CDO" ( that's in alpha order).

Torsion meter? I just used an inch-pound torque wrench. Keep in mind I sort of "half-assed" my differentials. I didn't full pull them apart, dial them in, measure contact patterns, etc. This is primarily because they were pretty close to "in spec," working fine (and quietly) before I pulled them, and will likely see light use under my ownership...Plus, differentials are scary and I'm working on a timeframe (truck is outside, in a driveway that isn't mine, and winter is coming...)

As for flash rush - the unpainted edge of that master cylinder is the latest on the list of things to piss me off...Might have to pull and coat it...

 

[Vae Victus]

Torsion meter? I just used an inch-pound torque wrench. Keep in mind I sort of "half-assed" my differentials. I didn't full pull them apart, dial them in, measure contact patterns, etc. This is primarily because they were pretty close to "in spec," working fine (and quietly) before I pulled them, and will likely see light use under my ownership...Plus, differentials are scary and I'm working on a timeframe (truck is outside, in a driveway that isn't mine, and winter is coming...)

As for flash rush - the unpainted edge of that master cylinder is the latest on the list of things to piss me off...Might have to pull and coat it...

I couldn't think of the name of it - Beam Type Torque Wrench. I was in a hurry.... Needless to say, I had to go to Amazon to get one.

Looking good! Keep it up.

 

[RWBeringer4x4]

Late last week, I got the spring painting finished, and locked everything down with my new center pins/spacers:

With the assistance of my little brother and a dolly, I managed to get the axle loaded back under the truck today:

Started installing the U-bolts, (sourced from Georg @ Valley Hybrids) only to find out that the new bolts I am using are actually a few thousandths of an inch larger than the ones I pulled out. I'm always happy with heavier-duty stuff, but this did result in the new bolts not fitting in the U-bolt anchor plate:

So, once again, I raided my future-father-in-law's garage, and found, quite possibly, my new favorite tool (perhaps tied for first place with my 4-inch angle grinder). Meet Thor:

Not sure how old this drill is, but it had to be over a horsepower. Made short work of boring out the U-bolt plates to accept the new bolts. Also made me realize how incredibly flimsy my forearms are!

 

[RWBeringer4x4]

So here is the next hickup. I've loosely mounted the new U-bolts and plates to the truck. As you can see in the shot below, things aren't quite lining up. This is especially true of the driver's side. I can't get the U-bolts to sit level and parallel. They want to tighten down at this weird angle:

The issue is less pronounced, but still present on the passenger side:

It's almost as if the bolts are conflicting with the sides of the springs/spring hangers, and causing the tops to splay out?

It doesn't seem like clamping them down will alleviate this, but maybe I'm just jumping the gun...Is this normal? Will torquing these to spec even them out?

 

[Stumpalama]

Open up the holes on the plates with a burr grinder so the bolts have room and don't give you false torque readings because the threads get hung up.. Next, as you tighten the the ubolts, do so in an "X" pattern and tap the top of the u-bolts inward as you do it, they will be fine.

 

[subzali]

My dad has a Thor as well. That thing is a beast!


...via IH8MUD app

 

[Vae Victus]

Rick - just curious - your axles are... where? I was going to mount wheels on mine once I finished, so that I could re attach the frame once I get the frame blasted and painted. (After the rear axle is done)

 

[RWBeringer4x4]

Rick - just curious - your axles are... where? I was going to mount wheels on mine once I finished, so that I could re attach the frame once I get the frame blasted and painted. (After the rear axle is done)

@Vae Victus - My axles are currently in the back of the Land Cruiser. As far as I can tell, there's really two ways to get your axles back under the frame.

1. Do what I think you're saying - build the axle out completely, wheels included, disconnect the front springs at the shackles and drop them, then roll the axle under, and reconnect the springs.

2. Do what I did - keep the assembly as "light" as possible, leave the springs attached, then put the axle on a dolly and roll it, long-ways, under the truck, then muscle it into position by rotating it up and through the springs.

I elected to take this approach, since my springs were sort of a bear to get connected. My hangers are a little "torqued" which made aligning the shackle pins a little tough. Plus, with my saginaw box, accessing the driver's side shackle bolt on the inside of the frame rail is tough.

Now that the axle is underneath and in position, I'll be loading in the axles, and moving forward with assembly (hubs, rotors, grease, etc). I just didn't start yet because I didn't have time to finish. As the truck sits out side, I like keeping the axle ends covered with plastic to prevent water/rust internally. With the axles/birfs loaded, there would be too much material to cover. basically, I'm hoping to get the axles and hubs installed in sort of an "all-or-nothing" effort one of these days!

The last potential sticking point is if I didn't grind enough out of the housing balls to allow for the large-pattern birfield clearance. They definitely fit when I tested them, but I've read some threads where torquing down the knuckle housing compressed the axle ball just enough to prevent the bitfield from sliding in...Hoping that isn't the case, but time will tell!

 

[RWBeringer4x4]

Having no daylight after work is really cramping my style...

Started plotting out the routing of my rear brake hoses tonight. I've decided to run my Monte Carlo calipers upside down (bleeders down), as this will allow for more effective hose routing. I'm trying to keep everything behind the axle, as much as I can (calipers, lines, etc.)

The short side will be easy - it's a straight shot from the Caliper to where the original rear axle hard line ran.

The short side, however, adds some complications. For one, the T-fitting/breather very close to the side of the axle. I'll need to find a way to run a (very short) hard line connection out to the soft line, but still keep the soft line out of the way of the bump stop, up on top of the axle.

Ideally, I'd route it in a similar manner to the long side:

The issue, however, is that this would result in two VERY tight bends in the brake tubing, routing it, essentially, directly backward from the T-fitting. I'm not sure if my flaring/bending can even manage something this short and crimped...we are talking 2 U-bends within about 3 inches of space...

The other option is this:

Put an S bend in the line to hold it up off the axle and prevent rubbing. Mount it to a tab on the front of the axle (but still up high) which in turn would give me a much straighter shot to the T-fitting.

Theoretically, this should keep it out of the way of the bump stop, in the event I ever maxed out the flex, but should still keep it out of harm's way (mostly).

I'm going to look around MUD and see what others have done here.

Any thoughts?

 

[handcannon]

First, I've got to say this, and I'm sure you already know this, but with bleeders aimed down you will have a difficult time bleeding the brakes. There would always be an air bubble caught in the upper part of the cylinder. You will have to physically remove the calipers from the mounts and turn them "upside down" to successfully bleed them.

Second, would it be possible to move the bolt on mounting brackets from the rearward position on the axle to the top of the axle and slightly forward from the 12 o'clock position? Like maybe halfway between the top of the axle and the forward facing position? It's been several years since I put discs on the rear of my 40 and don't remember if I was limited to just the rear and front positions due to the axle bolt hole locations, or if it would have been possible to place them at many different positions.

If this different location is possible it looks like it may possibly alleviate the bleeding problem and the brake line location problem. Just rotating the brackets about 135* looks like it might put the bleeders in an upwards facing position and would put the brake line on the front side of the axle and closer to the Tee on the short side of the axle.

I do remember in my searching prior to my disc brake mod that I couldn't find anybody having anything negative to say about different positions for the brakes.

Don

 

[RWBeringer4x4]

First, I've got to say this, and I'm sure you already know this, but with bleeders aimed down you will have a difficult time bleeding the brakes. There would always be an air bubble caught in the upper part of the cylinder. You will have to physically remove the calipers from the mounts and turn them "upside down" to successfully bleed them.

Second, would it be possible to move the bolt on mounting brackets from the rearward position on the axle to the top of the axle and slightly forward from the 12 o'clock position? Like maybe halfway between the top of the axle and the forward facing position? It's been several years since I put discs on the rear of my 40 and don't remember if I was limited to just the rear and front positions due to the axle bolt hole locations, or if it would have been possible to place them at many different positions.

If this different location is possible it looks like it may possibly alleviate the bleeding problem and the brake line location problem. Just rotating the brackets about 135* looks like it might put the bleeders in an upwards facing position and would put the brake line on the front side of the axle and closer to the Tee on the short side of the axle.

I do remember in my searching prior to my disc brake mod that I couldn't find anybody having anything negative to say about different positions for the brakes.

Don

@handcannon -

Yes, I'm aware that running the bleeders upside down will result in a difficult bleeding situation. The plan would be to rotate the caliper up, wedge some plywood in it's jaws and bleed it upright prior to installation.

There are basically 3 "good" positions to mount the calipers

1. Forward-facing, bleeders up (as the are designed to go) which sets them at about 2 O'clock. There is a definite advantage to routing the lines here, I agree, and it would make bleeding easier. This issue is, then your lines (and calipers) are on the forward-facing side of the axle, which would make them more prone to rocks/debris snags. It also mounts your lines on the bottom of the caliper, which means they have to run up the front of the axle to connect to the hard lines (or run underneath, where the leaf spring conflicts).

2. Rearward, bleeders down (like mine). This sets the calipers at about 10 O'clock, on the back of the axle. The issue then becomes routing the short-side line to the T-fitting in a manner than makes sense. In the future, I might try to find a hose with a banjo on one end (caliper) and a male fitting on the other, and just run it straight into the T fitting. The advantage here is that most of your lines are then run behind the axle, and your calipers are still high, out of harm's way, and protected by the axle.

3. Rearward, bleeders up. The major disadvantage I see here is that your calipers wind up mounted at about 8 O'clock, beneath the plane of the axle, which makes them rock bait. I also had a hard time finding a GOOD way to run the soft line up from underneath to the top of the axle where it would meet the hard line. This is partially because my soft lines are really short, and partially due to the location/close proximity of the inlet on the caliper being close to the leaf spring and U-bolt in this position. Definitely my least favorite, but it would make for easy bleeding.

I've been going back and forth between #1 and #2. I may still end up running the calipers forward, as I do agree that it would solve the line routing issue. I like the added protection of running the calipers on the rear, and I think I could make the soft line routing work (the S bend, above). It would make for tough bleeding, but let's be honest - how often does that need to be done - once every 60,000 miles? Maybe even less? My Mazda is approaching 100,000 and has never had to be bled... This truck is a weekend cruiser, mostly, so the chances of it seeing that type of mileage in my lifetime is pretty limited. As a result, I'm just not sure that easy bleeding should be a priority. That said, it will probably never see any rocks/obstacles that would really tear up my brake lines, even if they were run low and forward, so there is that side of the argument as well...

 

[pb4ugo]

I hate the the idea of the bleeder being down & the caliper being on the lower part of the axle. There's no reason to do it that way. You become the dreaded PO.

When you reference the orientation of the caliper by "time" we need to know which side of the vehicle we are looking at. The 40's I put discs on the rear, I position them at 2 O clock looking at the drives side, w/the bleeder being on top, the brakeline will be at about the same location as in your pics & behind the axle. To do this you will have to swap the calipers. In your pics you have the rt one on the left side & vice versa.

 

[SuperBuickGuy]

it's not terribly difficult to drill and tap a bleed hole on top.

 

[RWBeringer4x4]

I hate the the idea of the bleeder being down & the caliper being on the lower part of the axle. There's no reason to do it that way. You become the dreaded PO.

When you reference the orientation of the caliper by "time" we need to know which side of the vehicle we are looking at. The 40's I put discs on the rear, I position them at 2 O clock looking at the drives side, w/the bleeder being on top, the brakeline will be at about the same location as in your pics & behind the axle. To do this you will have to swap the calipers. In your pics you have the rt one on the left side & vice versa.

@pb4ugo

That is a good location - I'll have to re-evaluate, but I think the holes in Poser's brackets don't line up to allow that. I'd need to mount them in 3 out of 4 holes, instead of all 4, or something along those lines. That was initially what I was hoping for, but I think there was an issue with the brackets that didn't allow for it.

Poser's own install shows the calipers mounted forward, and angled up. To me this still seems like a pretty safe location. Thoughts?

To be clear:

Under no circumstances am I mounting the calipers low. The only reason I'd be mounting the calipers with the bleeders upside down is so that they can mount HIGH and BEHIND the axle.

The only other way to have the bleeders up is to have the calipers facing forward. This seats the calipers high, and the bleeders up. The problem is that the hose comes out the bottom, which leads them to being low and in front, on the axle. This makes me sort of nervous, as it seems to make them prone to getting crushed. Part of the issue is that I'm working with a very short (8-9 inch) soft hose. How much flex is really necessary on the rear axle? Seems like the caliper location shouldn't really change very much in relation to the axle, as they're both bolted together, and stationary (no steering, etc.)

 

[subzali]

I would mount it however Poser recommends (which I'm pretty sure there's a post on this somewhere on MUD)

Most rear axle brakes use hard lines. I know this is aftermarket so not sure how much slop is in there, but I would think it still shouldn't need much.

 

[RWBeringer4x4]

I would mount it however Poser recommends (which I'm pretty sure there's a post on this somewhere on MUD)

Most rear axle brakes use hard lines. I know this is aftermarket so not sure how much slop is in there, but I would think it still shouldn't need much.

Poser doesn't recommend one, specifically, I don't think. That said, I'm reconsidering mounting them high and forward. Seems like that might make for cleaner hose routing, and easier bleeding, as @pb4ugo mentioned - and I really doubt this truck will see the type of terrain that would catch a brake caliper inside a wheel mounted above the axle...

My only real concern is the hose. I really like pb4ugo's mounting position (rearward, high) but I don't think this bracket will allow for it.