Caterham CSR front suspension rocker bearing modification

[repsna]

I always had problems with the rocker bearing. first after 3 years in 2009 with approx 45K km. The spigot and the  oilbush (sintered bronze) got stuck. Thereafter I fiddled stupidly along greasing until  found out this winter greasing oilbushes is wrong. I looked for alternatives also because these bushes are more suited for rotational and less for oscillating movements. I found needle roller bearing and this is what Install this winter: full complement open end needle roller bearings B 1212 (ID 3/4 OD 1 inch width 3/4) 3 pcs.  per rocker from Koyo but also available from others when you search, as a spigot I use a piston bolt OD 19mm and length 68mm, thie inner diameter of the piston bolt is somewhat larger thant the original piston bolt I made a sleve from a 0.3mm aluminum sheet. As a thrust washer I use  Iglidur W300 WTI-1220-01 washers ID 3/4 https://www.igus.at/product/131.  look forward how it works our this summer

questions welcome Hanns Per

[Croc]

Hi Hanns Per @repsna 

 

At what mileage point did the original bushings fail.  I know you do good mileage in your car - you are the Caterham development test driver!  My suspension rocker bushings are still going strong - I check them thoroughly each year.  The only suspension bushings that have failed on my car and had to be replaced were the wishbone rubber type for which I used a Powerflex Poly Bush kit to fix that.  I am intrigued by the mileage fail point as that will give me a guide when to expect it on mine. 

Thanks

mike

[repsna]

Hello Mike I realized it after 3 years maybe 45.000 km it was back in 2008/2009. The spigot was firm in the bush and oszillated on the the bolt!!! so maybe its good to become sensible after 20.000km or so?  Since then I fiddled around with greasing the spigot and bush which was wrong. Sintered bronze bushes are not made for greasing they are made for oiling with special oil I learned this only now after studying the issue. One thing I had in mind was to drill a hole in the middle of the rocker (from the top) and install a nipple for oiling easily to avoid changing bushes. Bushes are cheap. But then I decided to experiment with needle roller bearings.

 

I have powerflex for the rear suspension and for the front lower whishbones. But for the front upper whichbone the rear power flex bush became loose after 15.000 km.  So I made  (my son!) bushes from delrin and so far no play after 30.000 km.

 

Hope I could give You some helpfull feedback

Hanns Per

 

[ultimate]

Hello USA7's.

 

I am new to the 7-world and own a CSR since 3 weeks. What a car and what an Engine *happy*

 

I have the same problem with firm spigot/bearing at the front rockers of my CSR. It is not disassembled yet but I can feel that it is not the best anymore.

 

Does anybody know a seller for the OEM bearing and spigot? What is the best oil for those kind of bearing?

 

@repsna: Did your solution work out to be good? 

 

Cheers from Germany

Chris

[Croc]

Welcome to USA7s Chris!

 

The only place I know for the OEM bearing and spigot is Caterham who sell it integrated with the rocker arm here

https://caterhamparts.co.uk/csr/4770-rocker-assembly-front-csr-inc-bush-spigot.html

 

I would call them directly as it only shows one part available which is not helpful when you are going to need two!

 

Hans Per developed his solution which he explained in the first post of this thread.

 

I am lucky as my CSR has not developed this problem yet - I checked it as part of my winter maintenance.  I owned my CSR since new in 2010. 

 

 

[MV8]

If the shaft rotated one direction, the sintered bush oil would work much better but the constant direction change and lack of seals make grease more effective. If using oil, consider a heavy weight lube 75wt or thicker. There are special "grease-like" oils for sintered when the rotation constantly changes. Grease in general is essentially thickened oil. A grease fitting in the center of the rocker would be nice.

A machinist can cut replacement bushes from delrin rod, thinner wall to fit an oversize center pin for more bearing surface for the same load on the pin and less likely to spin the pin on the bolt if the bolt is not as tight as it should be. The center pin can also be machined for a flat and the rocker drilled and tapped for an allen bolt to engage the flat, preventing the center from rotating independent of the rocker body, no matter how loose the rocker bolt is. Another option is to ensure the center pin is as long as the distance between the flanges for a tight fit and the bush assembly is not (providing some rocker endplay is good). The center pin ends can also be cross-cut/serrated to bite into the flanges when the rocker bolt is tightened.

[ultimate]

Thanks for all your information!

 

I will disassemble it and see what is going on. ;-)