Overview
Time needed: 20 minutes. (including hand washing)
Difficulty: Not difficult, if you have the right tools 😉
Parts needed
A new hub. Please use ePer to confirm the right hub for your vehicle and also check with your supplier. Based on V84 of ePer there are three possibilities listed as follows
- Part 51754192 for non-ABS cars
- Part 7769902 for ABS cars up to 15th May 1999 VIN 0043319
- Part 46519901 for ABS cars after 15th May 1999 VIN 0043319
Warning
There are 2 different types of wheel bearing one for cars with ABS and one for cars without. If you fit the wrong one on to a car with ABS the ABS warning light will come on as the bearing contains sensors to tell the ABS computer if a wheel is spinning or locked (skidding). Because the sensor effected is motion related the warning light may only come on at certain speeds.
(In the UK a car will fail the MOT test if the ABS warning light is on)
Notes by Geoff Bowles
The last time I drove my barchetta, I described how the ABS light came on after a few minutes cruising on the motorway, following the replacement of a rear wheel bearing. When I had the car connected to the diagnostic computer, it retrieved a message to say that the ABS system had detected a phonic wheel with the wrong number of teeth. The phonic wheel is a toothed ring on the inside of the bearing, which the ABS sensor uses to measure wheel speed. My new bearing didn’t have a toothed wheel but came with a magnetic implant which – I assumed – was there to do the same job I have spoken to those who supplied the part. They say that there are different parts before and after a certain chassis number, and agree they supplied the wrong part for my car. I’m still a little baffled (as were DTR) as to why the ABS light only comes on when cruising at 70-80 mph on the motorway, and not when using the brakes…. When I changed the bearing, and installed new rear discs and pads, I happily road tested the car round my local country lanes with no problems….!
The main problem I had was that one of the little studs that holds the brake disc on had corroded and seized. They’re very soft metal and difficult to remove without damage, so it might be worth replacing those too…
Tools required
- usual tools for wheel removal
- 32mm socket, minimum 25mm deep
- A decent lever
- 8mm Allen socket (hexagon)
- Screwdriver and a small hammer
Steps
- Remove wheel and distance spacer if present
- With an 8mm allen socket or key, unscrew the 2 bolts (circled in yellow) holding the brake caliper.
- Pull off the brake caliper (don’t remove the hydraulic hose). Suspend the caliper on a bungee cord or prop it on an axle stand, don’t let it just dangle on it’s hose.
- Remove the brake disc.
- Remove cap using a screwdriver and a hammer
- Loosen the 32mm nut which will be very tight
- Remove nut (1), spacer (2) and hub (3). The hub comes off easily.
- Install new hub, spacer and nut.
- Install the new bearing in the opposite order to the way the old one was removed.
- Note that the hub nut needs to be tightened to a torque of 280Nm. Most torque wrenches don’t go that high so you may need to borrow one
This technical guide was originally held at http://www.fiatbarchetta.com/btech/wbchange.html. It was copied to this site in 2021 to ensure its availability and to reformat it into a more modern layout. The original guide was written by Ivo Molák.
