Hi Guys, need your help on this.

I have a problem with my B310 during cruising at speeds beyond 60kph ++
The rear end of the car seems to be unstable and it swerves left and right for no reason. Even on a straight road, i can feel the back end is not synchronized with the front.

I changed the axle bushes (all 8 of them), changed the tires, checked on wheel alignment and also checked on the suspension, but problem still persists.

The car handles well most of the time during fast cornering (100kph++)..but when it comes to a straight & unlevelled road, the car just behaves abnormally.

Please help me to troubleshoot...advance thanks for your advice.

1. Tire problem: broken belt, bulge, mismatched tires etc.

or

2. Wheel alignment: Not enough castor, or toe-in is incorrect

Quote:

How low is it? It could be bump steering, although the fact that you say it somes from the rear is a bit confusing. If the car is steering itself when hitting bumps (steering wheel jumping to one side) and your car is low its likely its bump steer and could be helped by adding roll center correctors (a spacre which goes between you steering arm and the bottom of the strut.
Also get a alignment as suggested and get them to measure the toe on the rear. Ideally you want a little toe in on the rear (about +.5mm per side is good) if you have to much toe out it could make it a little unstable but, again that *should* show up in cornering with it feeling a little tail happy. Like DD said it could also be castor, I'm not sure what they came with factory but about 2 deg castor is a nice compromise between steering feel and handling. 3 to 5 degrees and steering will get heavy especially if you have a smaller steering wheel. It does however help handling and stability alot and you also get the added bonus of less turn in understeer
Sorry I can't be more helpful but thats all I can think of at the moment

I am assuming it has a coil rear end fitted. If so if it has been lowered has the panard rod been changed to an ajustable one. If not check that it isn't bump steering from being to low up front also check for broken centre bolts if still on leaf rear.

B310 has a live rear axle (as does B110 and B210), so if the rear toe-out is incorrect, there is no provision for adjustment. It should be 0 degres. If not a good alignment shop may be able to bend the housing to correct a minor imperfection. If it is out very much, the rear axle or housing is damaged.

VB310 (squareback wagon) used leaf springs.
WB310 (slopeback wagon) used coil springs.
No B310 used IRS, so it is unlikely there is a rear alignment problem unless it has been in a wreck.


Not sure about B310 castor, but B110 castor is minimal, and so the Datsun 1200 wanders more than most cars (which is normal for B110). Increasing the castor helps it track straight ahead much better than the stock specifications.

I was thinking if the problem was a result of a non std coil rear end fitted. I would be checking for front alignment, bump steer or broken centre bolts. Front swaybar linkpin rubbers can transfer some looseness to the rear. Check U Bolts.

Thanks for the inputs.

DD, the front tires are new (changed it abt 2 days ago)..but however, the problem still existed before i changed them. So, i would rule out its the front tire defect.
Secondly, the camber for both front tires are at -1 on both sides. I'll check for toe and castor settings later today.

nick_m, i dont think its bump steering since its happening at the rear. I faced bump steering issues long time ago, and changing the idler arm solved it.

Based on all your inputs, im suspecting it could be the rear toe. This part normally would be neglected since the setting could not be adjusted. By the way, any tips to get the rear adjusted? Im not sure on the toe, but the camber readings shows -0.5(left) & -0.6(right).

Thank you

Camber won't cause this.

There is no adjustment for the rear toe. It is a live axle so the toe-in is non-adjustable.

Yeah what DD said, unless you get the housing physically bent. Which can be done, but this is done to a bare housing normally on rebuild. The hard bit would be finiding someone to do it with any degree of accuracy.
Or just get a replacement and hope its better.
But definitely get a Wheel alignment and find out where you stand.

Rear left toe = 0.25deg
Rear right toe = 0.3 deg

Also observed leakage on my rear left absorbers. Can this be the root cause?

Thanks