Heathroi writes:
Remember the Focus with the wandering rear that I thought (ha!) might need lower profile tires?
Well as an update, it didn’t need tires at all. It needed new bushings all though the rear suspension. Which turned into a mammoth job of taking the rear suspension apart, cutting rusted bolts, frequent trips to the ford dealer for new control arms and lower A arms but back together in working order, like its new again.
Sajeev answers:
Good. I never understood how sidewall flex was a problem on a Focus. I mean, you’re not exactly driving Dolemites’ Cadillac in an SCCA event. It’s good to hear you found the real problem: high-speed wander is because of play in steering and/or suspension components, not from the relatively short sidewalls on a modern car.
Bonus! A Piston Slap Nugget of Wisdom:
The mixing of Pistonhead and Gearhead often makes for poor diagnoses. Many (including myself) are guilty of engineering the need to buy unnecessary parts. For example, I suspected an ignition misfire and used that reason to buy MSD coils. In fairness they were cheaper than OEM replacements, but I was still way off the mark: my funny vibration was a collapsed engine mount. Fail!
We must take stock of our mistakes and learn from their lessons. For starters, always seek out the most detailed explanation of the problem. Then follow time tested (or manufacturer-specific) diagnostics to isolate the problem.
If more repair shops followed this advice, we’d have many more satisfied customers within every brand. Not just the brands that complain about a “perception gap” while their operations circle the drain, either.
It needed new bushings all though the rear suspension. Which turned into a mammoth job of taking the rear suspension apart, cutting rusted bolts, frequent trips to the ford dealer for new control arms and lower A arms but back together in working order, like its new again.
Reason number one in favor of a good old fashoned live rear axle (or a beam axle if you insist on front drive). On some kind of exotic european sport sedan that thrills the driver with its oh-so-elegant road manners, then OK. But this is supposed to be an economy car, folks. This ain’t economy.
I had an ’84 CR-X with a wandering rear. First I thought it was an alignment problem. In the end the rear wheel bearings were too loose. What did I expect for a car I bought from a buddy for $150. He paid $50 for it and I traded it for a Hyundai Excel that I later sold for $900.
Just took me 10 mins or so to adjust them.
Am currently replacing the first section of exhaust pipe on my ’97 VW Cabrio. The flex joints are trashed and cause a weird vibration at 4500 rpm. Of course I replaced several unecessary parts first like motor mounts a couple of years ago just like th author mentioned in his article.
Honda gave the FWD/AWD CR-V engine the ability to rock during shifts by bringing their pipe down the front of the engine, under the oil pan and bolted it to a bracket under there. Then it connected to the rest of the exhaust system with a spring loaded “ball socket” (for a lack of a better term). Front pipe has a curved lip that fits into a curved seat in the other pipe and it’s all held together with springs and bolts. With enough ice and snow shoved under the car the joint will leak but 99.9% of the rest of the time it works flawlessly. Good now at 175K miles.
The Germans gave the Cabrio a pipe between the firewall and the engine with folded “bellows” that flexed, a wire cage to keep out road debris, springs to limit flex, balls and sockets to create a hinge effect, etc etc. And it lasted 150K miles. Sort of. I did not leak for 150K miles but now I understand it was the cause of the vibrations I would get under hard driving that I felt way, way back at 100K miles.
Keep it simple VW – okay?
Oh and to the Live axle guy – no way. Owned many live axle cars over the years. 4 wheel IRS is the ONLY way to go. For me it is a requirement just like disc brakes on the front wheels or more than three speeds (i.e. no automatics at my house). Good quality vehicles won’t have bushing troubles very often. 175K miles on our Honda and we have all the original bushings save the $10 front sway bar bushings and this car even has the original struts that have alot of life left in them. And yes – this car has been down some trails and towed some trailers…
I would add a recommendation for replacing suspension bushings with polyurethane. They are stiffer and do make a little noise (at first anyway, but a little anti-sieze fixed that) but are much easier to get in and out.
I would also add to the nugget of wisdom: if your detailed explanation of the problem fails to lead you to the root cause, start with the easiest and cheapest problem to fix when throwing parts against the wall.
guyincognito: poly bushings are fine if you live in a place with smooth roads. The banging and vibrations they provide in places like Houston is way too much for me. Or as I like to put it, if you want something that REALLY handles well, sell your sedan and buy a real sports car.
Nice addendum on the Nugget, because nothing’s worse than throwing parts at a problem.
@ Sajeev,
I’ve driven in Houston and it is certainly not worse than Boston or Detroit. Perahps I just have desensitized teeth. Or the experience of torching, drilling, and hacksawing my RTAB’s out and later paying several hundred dollars to have my LCABs and subframe bushings pressed out hardened me.
guyincognito: I agree about your analysis of roads…and from what you’ve done, you are certainly a stronger man than I. I’d probably wince when the transmission shifts and complain I can feel it through the seats of your car. Just kidding…I think.
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Before I forget, I gotta give props to RF for that picture related to my obscure reference. Nicely done!
As for “Engineering Need (to buy unnecessary parts)” the solution is simple:
1. Start with the assumption that “stock” is the best way to go. Presumably your car was designed by competent engineers. The aftermarket parts world is usually 99% form and 1% function. Style being the focus rather than engineering most of the time. I know I’m tempting the flames by that statement but the collective denial of this situation among car guys is phenomenal.
2. 99% of the time a car’s mechanical issues are due to some item having worn or failed in some small way. Get out your Occam’s Razor and spend some time troubleshooting before you peruse the parts catalogs.
3. The only exceptions to the above rules on a street-use car are things that have either improved with engineering progress, or have made finding stock replacements impossible. Converting a points/condenser ignition to electronic for example. On my mid-60s sports car a Mallory Unilite distributor went in back in 1999 and I’ve never even LOOKED at it again since. I’ve also installed 6″ tubeless wheels as buying tires for the stock 5″ tube width these days is damn near impossible. They still look stock, so only an expert in the make & model would spot the difference. They actually (and counter intuitively to most rigid-thought car guys) REDUCE the handling properties of the car, but given that I can find tires for it anywhere and I take long road trips in it, I’m happy with the compromise.
–chuck
On VW front control arms, the front bushing is the handling one, and the rear bushing is the ride one.
->It’s much better to only do the front in poly and the rear in R32 HD rubber versions.
Check for play in the front and back suspension and steering systems whenever you rotate/change tires and you should be able to catch problems like this.
Sorry for the O.T. post, but what kind of car is the white one in the driveway in the photo?
shaker,
I think it’s a UK-built Ford Cortina MKII. From around 1968.
Thanks!