Suspension restoration

The taut handling of Jeremy Haworth’s 2007 VW Polo had definitely softened with age, so it was time to turn its clock back to zero.

Released in the UK in September 2007, the Polo 1.4 TDI was the first of Volkswagen’s supereconomical Bluemotion vehicles. To help obtain the then record fuel economy, the company used the lower and slightly stiffer sport suspension from the Polo GTI and other vehicles in the SEAT/SKODA line-up.

We bought one of the first cars imported and an early impression was that of rattling teeth on the first speed bump encountered, meaning it was far firmer than the Renault Laguna it had replaced. After more than nine years and 116,000 miles, the suspension is noticeably softer. We could even push the front corners down by 25mm!

Our history is that the rear springs went very soft after 25,000 miles – one of various niggles about the Spanish-build quality control – and were replaced with new ones bought from VW as the parts aftermarket at the time had not caught up with the fact that the Bluemotion’s springs were ‘different’. Even VW had to place a special 24-hour order for springs from Germany. Fortunately, the replacements were better made and were up to the job for much longer.

Which is more than could be said for the rear dampers, one of which suffered what appeared to be a distorted piston rod at 55,000 miles and had to be replaced, while the other looked horribly corroded at 80,000, although when off the car it seemed to be just as firm and resilient as a new one.

Shake-down

Now the time has come to restore the suspension to as-new, meaning new coil springs all round and new front dampers, on the basis that the rears were changed fairly recently. For this, we took the Polo to Mendem Motors in Tadley, which has a dynamic balance testing system for suspension. You drive the vehicle onto plates, which then vertically agitate the wheels, giving response data depicting movement and relative values on a screen and a print-out. Beats the manual bounce test any day! It showed that our Polo was dynamically balanced left and right, ensuring even handling and braking stability.

While the old springs were noticeably softer than the new ones when given a hands-on shove, the 116,000-mile front dampers had absolutely no gas pressure, nor much in the way of resistance in the hydraulic department. Absolutely none of this would show up in the MOT, although industry sources suggest that most road dampers are below par after 60,000 miles.

A trawl on the internet revealed that no single supplier could supply both front and rear sport springs and dampers. In the end, GSF Car Parts supplied Oe-spec Boge front dampers, while Brake Lines One Stop Shop had a full and extremely detailed listing on ebay of high-quality German Suplex springs.