My car just failed MOT due to rusted body sill around a jack point area. Click here to see the video of the problem uploaded on youtube.


  • What job does it need done?
  • Is it necessary for welding to be done, or will just cutting out the rust do the job?
  • What would be the estimated price (or labour time) of the repair (in £?)?
  • It is impossible to say how long it will take to do it properly from that video. When the mechanic cuts away the bad bits we can see, it could reveal a bigger problem with the inner panels of the sill. – HandyHowie Mar 15 at 15:43

You need to cut away the rusted material.

This will need to be replaced and it must be welded into place - pop rivets and screws are not sufficient. The repair should provide the same structural strength as the original.

Replacement sills either complete or sections are available. If not a good shop will make suitable sections as needed.

Any asking of price can make your question off-topic, but that you should have seen in the faqs for the site as prices of labour etc vary around and between countries.

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  • I understand that the price will be very location dependent. But I did also ask for an estimate of how long this job would take for an average mechanic. Then I could just multiply it by the rate. Most mechanics I went to (in UK) charge ~£50/h. – Marcin22 Mar 15 at 9:37
  • @Marcin22 the good ones I use are £100 per hour... – Solar Mike Mar 15 at 17:07

As Mike says, you need to cut out the rusty metal and weld in replacement. The sill is a structural part, and so needs to be strong, and any rust repairs for the MOT have to be fully welded.

How long it will take (and so how much it will cost) will depend on several things:

  • Can you get pre-made replacement panels, or will they have to be fabricated?

  • Can you do the preparation and finishing yourself, or do you need to get the welder to do everything?

  • Do you want a top-quality job, or will a couple of visible seams be acceptable to you?

All of those can reduce the number of hours of the welder's time, and so the cost.

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  • lets say that visible seams are fine with me, I cannot get pre-made replacement panels and prep work and finish is done by the mechanic/welder. How long would that take? – Marcin22 Mar 15 at 10:08

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