Tuesday, April 21, 2015

Them's the Brakes. And the Breaks.

Okay, full disclosure. Cars like this old Volvo use a panhard rod, or panhard bar, to ensure that the body remains above the rear axle while driving around corners. But as I mentioned a while ago, the new axle for this old Volvo came with a panhard rod bracket that was located on the passenger side of the axle. The original axle had its bracket on the driver's side.
Of course, this means that we had to move the bracket from where it was over to where it would actually do something other than look funny. And my welder is a cute little 110 mig which, though terrific for all the light duty stuff I've had to do so far, just isn't burly enough to secure the bracket to the axle. Well - it could secure the bracket, but it likely wouldn't hold up to the forces of the .9G corners we'll be navigating every three tenths of a second from now 'til eternity.
Anyway, we got to the point that the car was completely ready to be driven except that it didn't have a panhard rod  and I was just too excited about everything, so (full disclosure is now)I drove it up and down the street a number of times to see what it's like to drive with all that new stuff fitted between the bottom of the car and the surface of the road. Everything I've done thus far has been geared toward making the car do better in corners than it used to, and here I was driving in straight lines, making U turns at .05 mph at either end of the street.
It's not for me to say what others should or shouldn't do. I will say, though, that it isn't likely safe nor smart to drive a car that's absent a critical suspension component. Nor one that's lacking the seatbelt anchor typically found atop the transmission tunnel.
At the first opportunity, I made an appointment with a local fellow who likes Volvos, owns a big macho welder, and happens to also have a truck and trailer suitable for moving things like cars around. When the day finally came, the old Volvo rolled out of the garage, and then my young son saw it sitting there. Something that's the same color as his Radio Flyer ('Drop Your Shorts Red,' I believe it's called). With shiny stuff and handles. He opened the door himself and climbed into the driver seat. Himself. Where there were more shiny things and handles.
Certainly, this interest will turn out well in years to come.
Getting the bambino out of the car was unpleasant for everyone but we managed that, and then drove the car up onto the trailer. I've mentioned the need for ground clearance in this car, and while loading it onto the trailer, I demonstrated that it needs more of that before we go to Mexico. I did this by banging the muffler - HARD - against the edge of the trailer and tearing not one, but two holes in the thing. The muffler, not the trailer. This did not, alas, result in a more race car sounding exhaust.
Apocalypse Cider Secret Volvo Lair, with right hand drive 123GT, a 122 and a 242T in attendance.
I figured it'd take about an hour to weld the bracket onto the axle and that I'd be home in time for lunch. My beloved bride had already told me that she knew I'd be gone most of the day, which I enthusiastically denied, mostly because I like spending my Sundays with her and our son. More of that "if I wish hard enough, maybe reality will surrender to my whim" thing I do.

She was exactly right [again].

Once we had the car on stands and everything lined up the way we wanted, it was obvious that we needed  a spacer between the panhard bracket and the axle. The brackets have to be the right distance apart, and they also have to be aligned so that when the panhard bar itself is in place that nothing is torqued against a bushing or wedged or compressed against anything and you can get things apart and back together again without a lot of fuss. What you want need, basically, is to have Zero Load (in any direction) on the panhard rod while the car is sitting prone on its suspension. Or maybe I should call it Zero Preload. Whatever.

For those of you interested in tuning archaic suspensions, you can change the roll center of the car by moving the ends of the panhard rod up or down (this, in turn, moves the center of the bar up or down, which is what really makes it all happen. Sort of. I'm paraphrasing.) I considered this, and then chose to not modify the panhard arrangement beyond the design limitations of the car as it was and the axle as it was. The original PV panhard bracket locates the axle end of the bar a couple inches higher than the one we're using, so the bar is lower than it used to be - but that's just how it worked out and not a calculated placement. The car, the panhard rod and the roll center are all somewhat lower now than before, and that will be just fine. And if it isn't fine, we can change it later. But for now, the task was 'getting the thing on the car.' And really, I don't tune suspensions to that degree. So far.

We had to move the axle bracket 1/2" aft. That's too much to build up with a gobby bunch of welding slag, and whatever we were to use for a spacer needed (and still needs) to be extremely stout.

Chris brought over his welding cart, and I immediately understood why he'd mentioned that it would be simpler to bring my car to his place than his welder to mine.  The monstrosity berthed in his shop makes my welder look like a toaster. And the cart also carries a plasma cutter, which might be the coolest thing ever. He found a piece of steel pipe that had an ID that matched the axle's OD and was - most excellently - 1/2" thick. After running that through a horizontal band saw and then a chop saw and then some plasma cutting, he'd made exactly the spacer that the car needed. And then with the welder they once used to build the Death Star, he welded the bracket onto that.

Plasma cutting.

You might think this is not pretty. I might vehemently disagree.
 ... and once those pieces became one, the axle received its new panhard rod bracket:

The gas tank isn't in the car, if that's what you're wondering.
Because I frequently come up short in the sensibility arena had no reason to think the car was anything other than ready for the road, we put the gas tank back in, added some fuel, and I drove away. The roads between Chris' house and my own are deliciously full of twists and turns, and I was beyond eager to see how the car felt. Unfortunately, I immediately found myself behind the Slowest Guy On Earth, who was sleeping behind the wheel while  towing his boat and trailer from somewhere lousy to somewhere even lousier. Cornelius Pass Road is perfect at 40 or 50 mph, and the speed limit is a reasonable 45. We kept our speed between 10 and 25 mph. I'm not kidding. I was downshifting into first for some of the corners, and never got into third until we emerged out of the forest and into the farmland where the road straightens out and becomes less interesting. But the car felt great. Steering and ride quality are, so far, the best they've ever been in this old PV since I've owned it. I ran over all the potholes on purpose just to feel the bumps; and I wiggled the steering wheel back and forth a whole lot just to enjoy the instant changes in trajectory without the slightest hint of body roll. Not that there's a lot of body roll at 13mph. But still.

I'd been using the brakes a lot while not running into this silly boat, and right about the time the road opened up, I could feel something (like brakes) slowing the car down. I'd wanted to give the rears another round of bleeding but hadn't yet done so, and though the pedal felt just a little bit spongy, the brakes - overbuilt for a car 1000lbs heavier - had no trouble putting a stop to things. They were safe, just not perfect.

Eventually, the sticking brakes were stronger than the B18 engine in 4th gear. Then 3rd got laborious. Then we stopped at the side of the road. Stopping was easy - I just took my foot off the gas pedal and watched smoke roiling out of the wheelwells as the car came to a halt. I thought about the fire extinguisher that was back at the house. After a 20 minute cool down, everything freed up again and I drove home like normal, cruising highway 26 at a smooth 4500rpms.

Given that the brakes had been fine until they got some heat (from braking, presumably), I figured that there must still be air in the lines or - more likely - in the calipers. When air gets hot, it expands, which then pressurizes the brake system (which is what makes brakes act like brakes), and the pads push against the rotors, which causes drag, and the drag causes more heat, and the additional heat leads to the air further expanding. This isn't what always happens with ineffectively bled brakes, but it happens often enough that even I know about it.

What didn't match with my brilliant theory was that both the rear AND the front brakes were dragging. The rears were the ones that needed another round of bleeding, while the fronts, I was certain, were fully and effectively and properly bled. But the front brakes were also sticking. Poop.

I called the tech support line at Wilwood. I like to pretend I'm super smart about old Volvos and brakes and stuff, which means none of their PhD engineer braniacs could possibly know more than a slouch grey haired ex punk kid whose automotive professional history includes breaking a lot of things and taking a lot of cars apart.

Justin answered Wilwood's phone, and as soon as I shared my 'not bled right' theory with him, he cut right to the chase. The master cylinder I'd bought contains what are called "Residual Pressure Valves" in both braking circuits, and the ones I have are rated for 10psi. These are very good things for drum brakes - so good that even in the Bone Age when the car was built the first time, the original PV master cylinders all came with valves such as these. If this blog was about converting front drums to disks, I'd have already talked about taking the valve out of the original equipment PV master cylinder. Because if you don't, your front brakes will drag. Disk brakes (like those in this 444) don't need 10psi residual pressure valves. They need no residual pressure valves whatsoever. If you feel the need, you can use a 2psi valve in each circuit. I feel no such need.

It had not occurred to me - nor the person who wrote the instructions - that this fancy new master cylinder might happen to have such things installed. I'd assumed that anyone cool enough to use a master such as this was already cool enough to be using disk brakes all around. Whups.

Those little black things and the springs above them have to come out.
About the time I'd finished putting things back together, Peter showed up to help bleed the brakes for the hundredth time. We did that, then went for a quick drive and I was happy to find that the brakes feel like brakes, and that (at least so far) they aren't sticking.

But the horrible "chuff chuff flutter chuff" leaky exhaust sound coming from directly under the floor was getting worse the more I drove, and I realized it would drive me completely crazy within a few days minutes. Besides which, it was making a car that's supposed to be all kinds of badass sound like a clapped out piece of neglected crap car instead of the requisite all kinds of badass we're after. It also filled the cabin with stinky fumes and made my eyes burn, which probably isn't good.

Because I didn't want to spend a lot for an exhaust that's essentially a temporary piece, I went to the local Baxter's (FLAPS - Friendly Local Auto Parts Store) and picked out a 45 degree bend and a cheap copy of the old school Cherry Bomb Glasspack muffler. The exhaust now exits in front of the right rear tire, and does exactly what it's supposed to: barely quiets the engine. I won't recommend this for a daily driver passenger car kind of thing but it suits this old Volvo's purposes nicely. And if I break it like I did the last one, I'll only be out $30 instead of the $225 I paid for the custom fab piece that's now destined for the recycle bin.

Now that the car is, other than these frequent teething pains, roadworthy, I'll be driving it whenever I have somewhere to go (unless the kiddo is coming along). I know that there'll be more adjusting and tuning and tweaking along the way - that's how it always is with something like this - but mostly, I'm really looking forward to Phase Two. That'll be the part where the interior (which is perfect and oem and for sale) gets removed and we go about installing things like a roll cage, proper seats and belts, a fire system and fuel cell. Unless something goes really sideways, I think this is just going to keep getting more fun.

'til then.

Thanks --

1 comment: