Project Rally Saab 99 | Magazine Series Part 8: More Brake and Suspension Upgrades

Update by Per Schroeder to the Saab 99 project car
Dec 30, 2020

Photography by Per Schroeder

When it comes to rally events, there’s a simple gauge of success: Can you drive the car onto its trailer afterward? Our Saab made that all-important trek up the ramp after the incredibly brutal Susquehannock Trail Performance Rally, so we considered the outing triumphant. In fact, the car’s body only sported a few new nicks.

Underneath, however, the story was quite different. The event lived up to its punishing reputation by ravaging our brakes and shock absorbers. We broke one damper on an early stage, and our brakes felt like they were well past their prime. After arriving home and unloading the car, we also noticed a puddle of transmission fluid on the trailer deck. 

Our next order of business was to rejuvenate and improve these areas. If we worked quickly and fixed our growing list of problems, we figured, we might even get to run another event before the season ended. 

Real Brakes, Real Easy

We first tackled the oil leak and brake issue by pulling the axles, brakes and outer hubs from the front of the car. The transmission leak was a simple fix once the axles were removed, as we just popped in a new right-side axle seal.

Next it was time to redo the brakes. Treating a Saab 99 or early 900 to a low-buck brake upgrade is simply a matter of bolting on some 1986-’87 900 Turbo ventilated rotors and calipers. The switch requires later hubs and outer CV joints, but there is no fabrication involved—just swap out the parts for improved fade resistance. The calipers even use the same pads. 

We tried this modification and found that while the brakes did last quite a bit longer during hard use, the car wasn’t slowing down as quickly as we needed. Our buddy Luke Sorensen has a 280-horsepower turbocharged monster of a 99, so we asked him for help.

Luke’s fix was clever indeed. He found that Wilwood makes narrow-mount calipers that bolt directly to the front hubs, as the 3.5-inch bolt spacing is a perfect fit for the Saab. 

He then matched the available bore sizes to the factory master cylinder. In the Saab’s case, the 1.62-inch bore calipers would work fine with the rest of the system.

We tossed the old single-piston, cast-iron calipers in favor of the aluminum Wilwood four-piston pieces. And at just $169 apiece, they were only a few bucks more than rebuilt factory calipers. We also lost a few pounds per corner and got larger and easier-to-find brake pads. 

Luke’s solution for the rear was a little more tricky, but with some good engineering and fabrication the solution was also fairly simple. He machined a pair of adapters to attach radial-mount Wilwood calipers to the factory axle. The 1-inch bore calipers are a good match to the rest of our brakes, and once again the aluminum calipers helped us lose weight and gain pad selection. The rear calipers are also affordable at $140 apiece.

The performance gains were noticeable. We found that the car had much better braking force, while the pedal was easier to modulate on loose surfaces. We chose a Wilwood track pad for our application; by the time we hit the first corner, these pads are warmed up and ready to slow us down. 

1: Our first brake upgrade used factory parts, as we simply bolted on a pair of vented 900 Turbo front rotors. 

2: Our eventual fix required a little bit of fabrication work; we used these custom aluminum adapters to bolt a pair of Wilwood calipers to the rear axle. 

3: We also installed a pair of Wilwood aluminum calipers up front. 

4: The Wilwood calipers (right) are significantly lighter than the stock Saab Girling units. 

5: As a bonus, the front Wilwood brake pads (right) offer more surface area. 

6: After breaking a shock absorber, we purchased another used set and had them revalved by Bilstein. This made for an inexpensive and effective setup.

Real Shocks, Real Easy

We originally sourced a set of Bilstein shock absorbers at the Carlisle Import show for just $80 total. These served us well for our first two rallies, and we rarely felt that more damping force was needed at the speeds we were going. However, since we suffered a broken rear unit at STPR, we’d have to come up with something new and improved before our next outing. 

We quickly found another pair of used rear shock absorbers, then sent the entire set to Bilstein’s Mooresville, N.C., facility to be revalved for our rally application. Rally shock absorbers typically feature very digressive valving to handle different types of terrain; it matches very soft high-speed damping for traction on rough surfaces with stiff low-speed damping for control over large bumps and jumps. (In this case, speed is actually a measurement of how fast the shock shaft is moving, not how fast the car is traveling.)

The Bilsteins were taken apart, revalved and sent back to us in short order. We noticed that the car felt much more composed over bumps, yet we could still feel the suspension soaking up irregularities as we powered around corners. Rebuilds such as this one are considered inexpensive in the world of rally, where shocks typically run $1500 or more per corner. 

Tarmac Ho! 

Our Saab 99 had been sitting—very prettily, we might add—for several months in our shop while we wrenched and awaited our next event. The time soon came to dust off the Swede and get it ready for a dose of tarmac. European Motorsports Park in Starke, Fla., hosted an event that featured a 64-mile tarmac rally. We were ecstatic that the tow was only going to be two hours—our shortest haul to an event yet. 

To get our car ready, we swapped out the knobby Michelin gravel tires for some Toyo R-compounds and reinstalled the anti-roll bars. The rally’s surface—a mix of deteriorating asphalt and fresh pavement—would put our braking and suspension upgrades to the test.

Tarmac No! 

It had to happen sometime. We suffered our first DNF at a rally, and it was a bummer. We were about halfway through the event on Stage 4 when the engine came to a screeching halt, ending our day. This was an unfortunate turn of events, as we were doing quite well—probably mid-pack in the small field. 

A superficial examination told us that something was wrong with the timing chain, and there was very little room to fix it with the engine installed. We winched the car onto the trailer and glumly drove home.

Once we pulled into the driveway, we took off the valve cover and saw that the idler shaft’s sprocket was broken. This meant the entire engine had to come out. Per’s dad, Pete, helped us remove the engine that afternoon. We knew we couldn’t get the car back to the event in time to continue, but we figured that the work had to get done sometime.

Stage rally is a two-person sport, and Dwain Cromer served as our navigator for European Motorsports Park’s tarmac event. We went in with high hopes.

The conditions were wet and dreary, but our Saab ran flawlessly—for a while.

The course featured some dirt sections between the surface transitions.

Sadly, our rally ended with a DNF. We pulled the engine later that day.

Once the engine was engine out, we were able to pinpoint the exact cause of our DNF: The water pump and idler shaft seized and broke the timing chain sprocket. The resulting carnage wound up costing us that engine block, head and pretty much everything except the pistons, rods and crankshaft.

We tore down a spare engine block and had it bored to match our high-compression Ford Pinto pistons. We then rebuilt the engine using the same bearings and crankshaft, all of which were still in good shape. The head was replaced with a rebuilt unit, and we put everything back together throughout the course of a few weekends. 

Along the way, we used a new chain tensioner from an MGB, which was cheaper and readily available. The Saab pieces have long been unavailable and are usually expensive when they can be found. The MGB tensioner was less than $30 shipped from Moss and, oddly enough, nearly an exact match for the Saab piece. A new timing chain was added to the mix as cheap insurance. 

Water Pumper

Instead of reinstalling the stock water pump, we removed the problematic piece and blocked off the passages in the engine block with freeze plugs; this would allow us to use an external electric water pump. We found three different options in our search for electric units, each with various strengths and weaknesses. 

A Bosch auxiliary coolant pump from a TDI-powered Volkswagen can be found for about $80 online and can cool our engine for a while—if it isn’t revved constantly. The good news is that it’s small, light and can be mounted just about anywhere. This is a common choice for sports racers and Formula SAE teams. 

On the other end of the scale is Moroso’s billet aluminum universal water pump. It’s about $325 and is capable of cooling a big, thumping V8 at full song. It’s a beast, though, weighing in at 8 pounds. Its size also means that its mounting must be carefully planned. 

Our seized water pump sounded surprisingly benign from inside the car, but in reality it caused considerable carnage.

Oddly enough, an MGB timing chain tensioner worked on the Saab engine. 

We sealed off the engine block’s passages with freeze plugs so we could use an external water pump.  

In the middle of the spectrum is the Davies Craig EWP110, which flows enough gallons per minute to keep our Saab cool at speed. At today’s exchange rate, the Austrailian-made electric pump costs about $200 shipped to the States. 

We tried all three options and found that the Davies Craig piece made the most sense for our application. We mounted it between the radiator and the engine and secured it to the inner fender.

To make the electric water pump work, we had to gut the spring and flapper valve inside the factory thermostat to allow continuous flow through the radiator. We wired our pump directly to a switched ignition source so that it runs whenever the engine is running. Our Saab is more of a rally car than a dedicated street car, so we chose not to use a more expensive and complicated thermostatic solution for its control. 

Onward and Upward

Despite the long list of repairs and improvements, our Saab came back together easily. That’s no surprise, as our experience with the car has made wrenching on it rather smooth and straightforward. 

The beauty of campaigning something so simple is that mechanical work can be quick and relatively inexpensive. And when there’s a strong chance that you’ll need to make field repairs out in the middle of the woods, simple is good.

Mission Accomplished

Building a 30-year-old Saab for modern stage rally isn’t necessarily about going fast. We entered for the fun and thrills of getting on stage and completing events, not for final position. Part of the challenge of a rally effort is finishing each and every event, and with a .750 batting average we’re feeling pretty good about how this project turned out.   

We purchased the 1977 Saab 99 a few short years ago with the simple goal of entering NASA RallySport or Rally America events. We didn’t want to be the folks bringing up the rear, and we didn’t want to enter the service areas on a tow strap. 

Our car initially needed a lot of rust repair and welding, so we used it as an opportunity to practice our sheet metal techniques. From there, we dedicated a large portion of our budget to safety equipment. We didn’t skimp on these items, and it shows in our final budget—more than half our cash is in the cage and seats.

The GRM rally team made it out to NASA and Rally America events from Florida all the way to Pennsylvania. The little Saab trucked through some seriously tough stages that would make a Jeep or a mountain goat stumble for footing. 

Building a rally car means learning a lot about the strengths and weaknesses of a regular road-going vehicle. Once the going gets rough, the car has to remain tough and solid through a lot of punishment. We seam-welded a good portion of the chassis and reinforced the suspension in precisely one zillion points. That just meant more opportunity to practice our welding and fabrication techniques. Of course, most of the fun of building a car is just that, the building.

However, it’s time to switch gears. That’s right, we’re moving to our next project: a vintage sports racer.

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