Rear wheel bearings

I was told the bearings had this number printed on it: "4EO 407 625 A SKF BAF-0076 C ITALY A 23 3 3347". Which after some Google magic indicated they originally belong to an Audi A6C6 2,0 T / 2,4 / 3,0. For us swedes it can be conveniently bought at Biltema for a nice price here. Or of course, the real deal at Caterham parts here.

I've read they're a pity to remove, but for me they came off pretty easily. The first one simply fell off, the other one was a bit harder. I got them off by using the bearing bolts as a puller by screwing them against the brake disc with a impact gun.

The cheaper Biltema version was identical to the existing bearings, except for the inner dust seal being made of metal instead of rubber. Metal seals are probably not as good but the bearings are easy to replace so I'll take the chance.

Fuel filter

MANN WK612/2 or MAHLE KL158. Available in your local car parts store.

Must be one of the parts on this car that is hardest to remove, and even harder to get back due to the tight location.

Take care not to get fuel in your eyes when releasing the pressure. (Don't ask..)

Front damper spherical bearing play

There was a play in the joint between the rocker arm and damper in the front suspension, noticeable when I jack the car up, removed the wheel and lift the suspension at the hub. I decided to change the spherical bearings.

• First step was to remove the dampers. Remove push rod from lower wishbone. Undo damper bolts starting with the lower bolt.
• The misalignment spacers on one of the dampers was tough to remove, but eventually they got out with some help from a blow torch. Warning! Heating bearings could give off hazardous fumes. These fumes can be harmful to the eyes and to the lungs, if inhaled. Source: SKF.
• Remove retainer circlip with a pointy sharp tool.
• Carefully remove bearing using a socket and a hammer.
• Bilstein part number E4-B46-610. Can be obtained from Caterham Parts or directly from Bilstein. You can also find similar bearings at your local bearing shop in different qualities. 
• When I fitted my new bearings I noticed a small play between the new bearing and housing. I used Loctite 648 retaining compound as glue. I don't want any movement there, or the shocks could easily be ruined. I hope the new bearings will outlive the shocks, as they probably is going to be tough to remove in the future. (Heating them might work)
• Reassemble. A good opportunity to replace the bolts and nuts as well. 

Note: I have the "race spec suspension" on my car. The procedure and part numbers may be different on the road spec dampers.

I changed the upper bearings on both sides as I thought that would be enough. Now when the suspension is reassembled I can still feel a small play in one of the lower bearings, sigh...

Replacing front bushings

I've noticed that my front wings move quite a lot when I brake, and that have become worse over time. I also have a brake judder on the front. My suspicion was the rubber bushings on the front suspension.

Working on cars are fun fun fun

Removing the old bushings was a real PITA. The worst thing I've done on the car so far. On the CSR the rearward lower wishbone bushings are located in the chassis in a very tight location. The front bushings are in the removable wishbones and a bit more manageable. But to remove the ones in the chassis takes lots of swearing and bloody knuckles.

I tried to press them out with a threaded rod, nuts and washers with no luck. At the end the only thing that worked was burning out the rubber with a blow torch and then sawing through the outer ring with a Dremel milling tool using an extension cable to be able to reach. The best thing would be to cut through on opposite sides of the bush but the tight location makes that (almost) impossible. Even then it was not easy to get them out but eventually they gave in. Be careful not to cut too deep and damage the chassis.

Bushings can be made up from many different materials with different characteristics.

• Rubber (standard)
• Polyurethane bushings (Powerflex among others)
• Delrin
• Nylon
• Rose joints

Except for completely stiff rose joints, Delrin is what racers seem to prefer because of their stiffness and self lubricating qualities. Unfortunately no complete kits are available in Delrin, and therefore I bought Powerflex bushings out of laziness. The opinions about Powerflex (and other poly-bushings) vary to say the least. If they doesn't work I can reuse the hardware supplied with the bushings and make up my own bushing material in Delrin.

Rubber bushings are not necessary wrong. But as I wrote, removing them is something I rather not do again. Other types of bushings are much easier to replace.

Despite of what Poweflex website says the correct part numbers for the CSR are four PF8-901 bushings and four PF8-902 bushings per car (front suspension only). They are sold in pairs.

The smaller PF8-902 bush comes with a special bolt as they're too small to have room for an inner sleeve, but I used the standard 3/8"x2.5" for the bottom rear bolt as the supplied bolt was too short.

Lets hope this works.

Mantorp wear and tear

An humid day at Mantorp with rain in the morning and dry after lunch. One of those days when nothing felt good. I pushed harder and harder but the lap times stayed high and today's best time was 1:23.0. A Camaro cup team confirmed that the track was slower than usual because of slippery rubber from drift cars the days before. Still I didn't feel like I drove as good as I could have.

A couple of other things didn't go very well either.

Cracked wing with zip tie

First my right front wing went loose and cracked. Back in the pit I drilled a small hole and put it back with a zip tie. The next lap the left wing went loose...

The oil catch tank got full and spew oil in the engine bay. I don't know how that is possible but that is what happened.

The exhaust manifold sealant didn't hold and the leak is back. Another winter project.

The orange colour is where the pad material ends.

Rear brake pads worn out completely. I have ordered a new rear set of Pagid RS4-2 (1158 for my calipers). When the front pads wear out I'll try a different brand and see how they compare. I'm also considering installing a pressure reducer valve to rears and use the same compound on both ends. (Right now I use Pagid RS14 on the fronts and RS4-2 on the rears)

The A frame bushings are worn. At least I think so. When I brake I can see the wings move much more than they did before. I'm thinking of replacing them with Powerflex bushings during the winter, but they sure are expensive!?

One more trackday before the winter, this time at Gelleråsen. Lets hope it doesn't rain.

Rear hub nuts

Both sides loose - scary! Left side so much I could turn it with my fingers.

41 mm socket.
270 Nm (yes that is a lot!)

New front discs and pads

Pagid RS14

Apparently I didn't change the front pads in time, so one of the discs had some ugly grooves a bit too deep for my liking. They're probably fine but I changed them anyway together with the pads. I also had a brake judder I was hoping to finally get rid of.

I found my left brake caliper had scars from a wheel bearing miss-hap a couple of years ago. I suspect that could have caused the pads to jam and that the brakes did not take evenly on the fronts. The pads on the left wheel was only half as much worn as on the right! Glad I found it and was easy to fix with a rasp.

After a test ride on a dark highway I found all brake judder was gone! It seems the new brakes has a more distinct "bite-point" than before. I don't know why because I had exactly the same model of pads and disc before. Maybe that's just while they're new.

AP Racing 10" vented disc

PAGID Pads 20349-RS14 (for the AP-Racing CP7600 4-pot caliper) €177 + VAT from Nimex Motorsport in Germany.

Brake disc AP-Racing CP3707-103P from Caterham £150 * 2 + VAT

Brake disc to hub torque: 35Nm + loctite

Brake caliper torque: 47Nm

Castellated nut torque: hand tight

Wheel bolts torque: 74Nm

Clean the new discs with brake cleaner

Grease bearings with high temperature grease while you have the hubs removed.

It is also a good idea to air the brakes while you have the wheels off.

Both the discs and the pads need to be bedded in.

UPDATE: Meteor Motorsport now sells AP-discs for Caterham!

Brake fluid change

Replaced the brake fluid. Used the same fluid as last time - ATE Blue racing.
Because I accidentally got some air into the system I had to remove the rear callipers and shake them around to get all air out.

I use Pagid RS14 pads on the front, and RS4-2 on the rear by recommendations from Pagid technical support. It gives me a good balance, but next time I might try one step more aggressive on the rear.

The Pagid part numbers are 20349 for the front AP-racing 4 pot calliper and 1158 for the Audi (?) rear.

Thanks to Levin Racing for their patience.

Spark plugs

Finally I changed the spark plugs. About time I'd say!

NGK BR7EFS
Gap 0,64mm
12 Nm