Caterham parts on order

[AndyB]

I just ordered a bunch of Caterham parts amongst them a complete rear bushing kit for $165. I'm tired of constantly replacing the "A: frame bushing and wondering if it's because I'm getting movement in the rear axle because another or several bushings are worn.

Does anyone with a live rare axle and no LSD get this symptom. I don't often do it but when I wind her up and drop the clutch the rear end steps out as it does when I shift quickly at red line into 2nd. Most other cars you would hear some tire chirp but Sevens when you can induce wheel spin don't seen to have enough weight to produce noise or smoke. So is the rear end stepping out due to a little tire spin or a little rear wheel steer?

[coffee break]

I purchased a 3rd or 4th hand used '95 Caterham from a guy who had owned others. He indicated he replaced the rear "A" frame bushings yearly. They are a wear item. I'm not as aggressive (so far) as you state, I've not experienced much stepping out (yet).

I prefer not to draw the attention of those guys driving the black & white cars. :blueangel:

[AndyB]

Sometimes I can get a season but throw in a couple autoX events and it can climb to 3 in a year.

[xflow7]

As above, replacing the bushings is common. I think frequency probably depends a lot also on your tolerance, annual mileage, and how much your diff leaks (gear oil is nasty for the bushings). You can get an A-frame that takes a spherical bearing to replace them.

 

I very rarely dump it in 1st gear out of kindness for my half-shafts, but mine also steps slightly to the side. It could be that other bushings are a bit worn, but also keep in mind that there's a lot of suspension movement going on in that scenario even if the bushings aren't worn out.

 

The reaction torque will cause one side of the suspension to tend to compress and the other to tend to rebound (think dragster). On top of that, the rearward weight transfer will tend to compress both sides. These movements will cause the ends of the axle to move fore/aft a bit, and not necessarily together, which can put a bit of steer angle into the axle. And to further complicate things, depending on jounce/rebound damper valving, the rate at which the two sides respond may be different.

 

So, net, it can't hurt to replace aged bushings, but I wouldn't assume that a small step sideways under a hard launch indicates anything amiss with the bushings. You may be able to tune some of it out by playing with rear ride-height, but it will have a corresponding effect on roll-steer and balance, so I'm not sure I'd mess with it if the car is otherwise handling well.

 

Dave

[AndyB]

Thanks Dave for all the information you make good sense, the dragster reference filled the void that was fast forming in my little plastic brain.

 

The A-frame that takes a spherical bearing, is it a direct replacement do you know or will I have to change the mount welded to the axle and will that setup just transfer the stress to another and possibly more expensive component?

 

I still hope to gain something with all new bushings as only the radius arm bushing have been replaced in the last 30+ years.

[coffee break]

I'm of the opinion that the rubber bushings are a mechanical fuse for the rear suspension. They are the first thing to fail. If the "A" frame is beefed up, then you will find the next weakest component, and more expensive and/or exciting to replace.

[Kitcat]

FWIW, I replace all rubber bushings on my Caterhams every 10K miles, or 5 years, whichever comes first. I just did this for the first time on my current Caterham and will be interested to see if it makes a noticeable difference on the track.

 

Similarly, I try to replace engine mounts on the above schedule as well. For some reason they dont last long and once the engine starts moving around out of spec, you have real problems. Some of my used ones have looked like the remains of those blown truck tires you see on the highway(:.

Edited May 21, 2014 by Kitcat

[AndyB]

Never thought about motor mounts. Mechanic that replaced both masters and the slave cylinders did say he noticed the nuts on the eng. mounts had backed off so put a wrench to them but he never mentioned condition.

I bet Caterham will not have them for the twin cam, perhaps Redline can help.

Thanks for the heads up.

[AndyB]

All 3 mounts are on order from Redline in the UK. I love e-mail so fast so inexpensive:)

[Kitcat]

Andy. Some of us X-flow owners experienced many mysterious problems, esp at the track, before this was diagnosed. Of course there was the occasional loud clunk, but also the motor would splutter on turns. Seems that as the engine worked loose, that the carbs' air filters wld be shoved so hard against the bonnet cutout that air wld leak into the intake system and screw up the A/F mixture. I had all sorts of theories, and a bad motor mount was not on the list. But when I fixed it, all the mystery problems were gone.

 

I was surprised abt 5000 miles later when the problem returned. Again, the mounts were already shot.

[TheDingo8MyBaby]

It was my experience that the motor mount (to clarify - enging mounting rubber instead of the engine mount bracket) on the right side of the car needed to be replaced most often.

 

Instead of ordering from the UK, XKE mounts are the same thing.

 

Found here for pretty cheap:

 

http://www.amazon.com/URO-Parts-C18556-Engine-Mount/dp/B0066RVGF4%3FSubscriptionId%3DAKIAJUWVMOP4RTVDXM2A%26tag%3Dstreetperform-20%26linkCode%3Dxm2%26camp%3D2025%26creative%3D165953%26creativeASIN%3DB0066RVGF4

 

You also may want to consider adding a large washer over the mount to distribute the load.

[AndyB]

That's interesting Kitcat, you'd never put that problem down to motor mounts. I had a starvation problem when I pushed the car hard into just right handers. It took me a while to nail down my problem and it should have been obvious. When the gas tank gets to half full it would appear, I guess it has no baffles.

 

Hopefully when the $200+ of rubber goods are installed, mounts and bushing they make a noticeable difference.

[AndyB]

No excuse now, bushings ordered Tuesday arrived Thursday afternoon.

Big question now, will my bench vice double as a press?

Edited May 23, 2014 by AndyB

[ihckb2]

When installing try some silicone spray for lubricant, unless they come with directions not to use silicone.

Maybe someone has a better lubricant to use.

When I did mine I had to make my own bushings and are synthetic.

Vice should work just fine or a large C clamp.

[AndyB]

Well she is going into the shop or perhaps just the parts to go under a press.

I had no luck removing the old bushings, couldn't find anything that fit the exterior of the bushing to push it out or some thing to hold the say radius arm and allow the bushing to come out. Like everything Lotus they are very thin walled.

[Kitcat]

When my regular mechanic did my first set of bushings he said he'd had to fabricate items to use to push out the old ones and it took much longer than expected. I took my next set to a race shop and they had everything they needed and said it was easy. Nothing like having the right tools.

[xcarguy]

Nothing like having the right tools.

 

That's an absolute truth in these circles. :iagree::iagree::iagree: