Sunday, July 19, 2015

Instillation of Matco Wheels & Brake Assembly Begins

Yesterday, in addition to drilling and lightly sanding the edges of the aft window, work shifted to installing the Matco wheel and brake assemblies. The Matco wheels and brake components had been left in the plastic wrap which turned out to be somewhat problematic because inside the bundle was an instruction book which left little to be desired. The printed instructions, what little there is, were easy enough to read, but the illustrated parts breakdown is, in my case, hard to read. However, after going online to Matco’s WEB site this morning, I discovered part of the issue … the illustrated parts breakdown is actually in color, which often prints out as light shades of grey making it hard to read. There is a chart that basically shows all the hardware with the exception of the brake line fittings gets torqued to 100 inch pounds. Return from the future: I questioned Matco about torquing the two AN4 caliper bolts to 100 inch pounds (which is twice the 50 inch pound low end value for an AN4 bolt). The answer: Matco said because the two caliper bolts use Nord-Lock washers, the increased torque value is to overcome the friction created by the Nord-Loc washers.

Other than the hard to read illustrated parts breakdown, there is NOTHING about how to disassemble or reassemble the wheels … NOTHING!!! Reading the Matco instructions left me with many more questions than answers. For instance, toward the end of the instructions is a section called lubricants. Here a specific type of anti seize lubricant is mentioned (which turns out to be graphite based) and is listed for wheel bolts and nuts …. Yet, there is no mention in the actual assembly instructions (or lack there of) to use anti seize lube on the wheel hardware during assembly. Return from the future: Matco said at one time different components were used which benifited from the anti-seize lubricant ... it is no longer required. Another inconsistency is the requirement to check for the required spacing between the brake pads and disc based on a reference to a drawing … but nothing is mentioned about how or what adjustments to make if the clearance is not correct. Return from the future: Matco said the caliper/brake position is adjusted to the disc at the factory using a Matco axle, because the wheel/brake assembly is installed using a Matco axle, no adjustment is necessary since it was already done at the factory. Only builders using third party axles will need to get involved with this adjustment. The bearings are to be hand packed with grease and all the ones mentioned are aviation greases. I went online to check the properties of one of them and it turned out to be a full synthetic with a NLGI rating of #2 …  after checking the synthetic grease already purchased for the bearings, it seems to have the same NLGI #2 rating and also a slightly higher temperature rating as well. So the grease already purchased is probability OK, but want to talk to Matco first … so will have to wait until Monday. Since this is Oshkosh week, will likely need to talk to them at the show. Return from the future: I could not get an answer from Matco about using a high quality synthetic automotive wheel bearing grease. They said they know the bearings will peform well with the recommended aviation greases.
Matco wheel and brake assembly disassembled for bearing packing and tire instillation … unit on right is as shipped.

As can be seen above, the Matco wheels and brakes need to be disassembled for instillation. The wheels are made in two halves which need to be split so the tube and tire can be easily fitted without needing tire tools to do the job. However, some care must be taken when taking the wheels apart … as the parts are marked with reference to the holes for the tube’s valve stem.

The half of the wheel that goes adjacent to the valve stem hole is marked as seen in this photo.

The hub is also marked so it can be placed adjacent to the valve stem hole … also note the hole this creates down below where the hub meets the wheel … this creates the exit point for the 90 degree valve stem.

The axle mounting hardware will change depending on if the builder is installing the wheel fairing kit or not. If builders installing wheel fairings follow the instructions at this point, you find yourself taking everything apart again to install the hardware for the wheel fairings. Builder tip: If installing the wheel fairing kit, do not install the two bolt washers highlighted in yellow in the following photo. Jump ahead to look at section 36 you will see the washers are to be removed when the U-00003 bracket mount is installed on the inboard side of the gear leg … which means all the bolts have to be removed so may as well install the U-00003 bracket and also omit the washers now so the work does not have to be done twice.
In section 36 for the wheel fairing instillation, the builder is instructed to remove the washers that are highlighted in yellow. Builders NOT installing wheel fairings will want to install these washers.
Photo of section 36 shows the instillation of the U-00003 bracket on the inboard side of the gear legs.

Decided I could go ahead and install the axle and U-00003 bracket mount onto the right gear leg. The four AN4-16A bolts were located and a feeble attempt was made to install the axle assembly. Of note, the two threaded holes in the outboard face of the axle need to be positioned so they are horizontal ... the threaded holes will be used later to install a bracket for the wheel fairing kit.
Installing the U-00003 bracket mount onto the inboard side of the right gear leg.

During the attempt to install the axle assembly along with the brake plate and disc assembly, it was quickly discovered that there was no room between the axle assembly and the locknuts to get a socket to slip over the nut … even tried the thinner 1/4" drive sockets and there was still not enough room.
Quickly discovered that what I attempted to try here did not work because of clearance issues with the nuts and no access for wrenches.

The two bolts going through the caliper do needed to be removed so the brake disc can be separated from the assembly … this will allow an open end wrench to be placed on the mounting nuts with just the brake plate installed.
With the brake disc removed, there is easy access to the axle nuts for an open end wrench ... also note the two threaded holes in the end of the axle need to be horizontal.
Tightening the four axle bolts with the brake disc removed.
Disc and caliper reassembled and ready for the hub with bearings and the wheel/tire assembly.

Not being sure about the grease, anti seize lube or rotor clearance adjustments, will not assemble any further until a conversation with Matco has taken place to clear up my questions.