After years of use, automotive finished leather can become worn and tired looking, and can often make an otherwise pristine interior, look old and unappealing. The option of a replacement is both expensive and very often unnecessary, and can affect the originality of your vehicle.
Leather restoration helps you or your clients add value and prestige to their vehicle, wither it be a daily driver, a Concours d’élégance entrant or a classic car. When the time comes to resell the vehicle, one with damaged leather will realise much less than one with clean undamaged upholstery so clients use renovation for commercial as well as aesthetic reasons.
As tough and durable as finished leather can be it can still suffer from wear and tear problems which can be repaired at an affordable cost compared to renewal. Finished leather upholstery is often the most costly item to replace in a vehicle. Small scale damage can be fixed with a localised repair quickly and smoothly i.e. cuts and cracks, scuffs and scratches, fading, stains and discoloration as well as general wear and tear
For more serious signs of age, wear and tear a full upholstery renovation will restore the leather to its original colour and lustre. This includes minor repairs and a total re-application of the original colour pigmentation. You do need to understand some of the basic chemistry behind the tanning and finishes applied to automotive leather to understand how to care for it
Successfully refinishing anything will depend on adhesion. Once the surface coatings have worn off or broken through, the hide itself is very porous, like a chamois. It then starts to absorb impurities like, dirt, grease & any conditioning creams that have been applied over the years.
The longer it has been left, the deeper these impurities absorb & the more difficult to gauge the success of the initial degreasing process. There is an additional problem in that we have to use the water-based coloured lacquers which are currently being used by the tanneries today. These need to be used on a totally grease-free surface. Another problem is the age of the leather requiring refinishing. New leathers rely on silicon or wax additives in the clear protective top lacquer to get them through the rub tests.
This obviously will give adhesion problems unless broken down first. Many softer automotive hides also have a cross- linker added to the top lacquer which makes it virtually impossible to break down without causing the remaining coating to break up with it.
This article provides you with an easy methodology, as well as some recommended, easy to use products to restore finished leather to an as-new condition (See also “Automotive Leather Upholstery Cleaning and Care” article)
There are three methods to upholstery renovation-
• Remove the covers and use an immersion dye
• Remove the seats, back cushions and head rests and spray pigmentation (applying pigmentation in-situ can be very messy)
• Renew the upholstery covers ( not an option for Concours d’élégance entrant vehicles)
Removal of the seats will make the installation / removal of the seat covers much easier, allowing access too hard to reach areas; it’s relatively easy if you take your time and are careful. Disconnect the battery before starting. Remove the battery terminals (negative terminal connection first then positive) and always put them back in the reverse order.
Some vehicles have airbags sensors in the seats but when you unplug the seat wiring harness with airbags or airbag sensors, the computer senses this and trips the light (s) and/or message, which must be reset by the dealer when you’ve re-installed the seats wiring harness
Front bucket seats are typically held down by four bolts on the ends of the runners at the base of the seat, two in the front and two in the back, these bolts are usually torque down hard (when replacing start the bolt by hand, being very careful not to cross-thread them) These are removed using a socket wrench.
Sometimes the bolts are covered by a decorative plastic moulding, which is held in place by a screw or just pops off using a prying action with a slotted screwdriver.
First, slide the seats to its rear-most position, exposing the front Torx head bolts, remove, then, sliding the seat to its forward position, exposing the rear bolts, remove.
When all four bolts have been removed, gently tilt the seat either forward or back to reveal any wires that are connected to the underside of the seat (seat position controls, heaters, seat belt and air bag sensors, etc.)
Carefully unplug these wires, and remove the seat from the vehicle, taking care not to scratch leather or paint surfaces as you lift out the seat. Cover the remaining wire harness with a plastic bag and then aluminium foil; this will prevent water and / or pigmentation solution from entering the wiring harness.
Caution- It may be necessary to have a dealership‘re-set’ safety air bag sensors and disarm / rearm the side-impact air bags(SAB) as they are installed in the seat. Improper disarming may result in injury if the side air bags deploy
Removal of Leather Seat Covers
Prior to the removal of seat covers or renovating the pigmentation it is advisable to apply Leather Master Soft Touch (ex Vital) liberally to surfaces and then allow it to sit for 20 – 30minutes, , this will soften the covers making them more workable.
You will need the following specialist tools- Hog-Rings, Hog-ring Pliers and a pair of Hog-ring Cutters or Tin Snips, which should be available from upholstery shops. If necessary take photographs of how the covers are attached to help you with re-installation. Be patient and take care when removing leather seat covers and ensure that the seams do not rip or tear.
Front Seat Cushion
For almost all applications, the first step is to remove all of the plastic trim pieces from the seats. Most vehicles have Phillips head screws or plastic push-pins that hold the plastic trim pieces to the seat. Make sure you mark which screws go where, as the screws are normally different lengths. After all the trim pieces are removed, flip the seat upside down, so the bottom of the cushion is facing you.
There are normally four (4) bolts that hold the seat cushion pan to the seat frame. Remove those bolts and remove the seat cushion pan from the seat. On some seats you cannot remove the seat pan and you will need to just have to work with the seat pan still attached.
There are either J-hooks (plastic channels that clip onto the frame of the seat) or hog-rings that hold the edge of the factory cloth/leather to the seat cushion pan. Remove these, and fold the factory cloth/leather up towards the centre of the seat, revealing the centre insert seam lines. The inserts use either hog-rings or Velcro® to attach the covers to the foam core. If hog-rings are used, snip them and remove the cover.
If Velcro® is used; simply pull on the cover to separate it from the foam, being careful that the Velcro® strip in the foam core doesn't rip away from the foam. If applicable, you may need to transfer the listing wires (metal rods) from the cover
Re- installation of your leather seat t is the reverse of removal. Start with hog-ringing the inserts, and then move to the edges. After you have recovered the foam core and seat pan, set it aside and start on the backrest.
Front Seat Backrests
First, remove the headrest and set it aside. On most vehicles, holding down the release button, and pulling the headrest up will remove the headrest. After the headrest is removed, flip the seat upside down again. If your seat has soft cloth/vinyl backs, you will see J-hooks, hog-rings, or a zipper holding the factory covers together.
Undo the J-hooks, snip the hog-rings, or unzip the cover and start to roll the cover up. There will be hog-rings or Velcro® holding the insert seam lines to the foam.
Remove the hog-rings as you roll the cover up over the seat. If your seat has a hard back, there will be a series of screws along the bottom that hold the bottom of the hard back to the seat. Unscrew these, and then pull open the hard back slightly to determine if the hardback needs to be slid up or down to be removed. Slide the back the appropriate way, and remove it. Now, you should be able to see the attachment points holding the factory seat cover to the frame. Undo these attachments, and pull the cover up and over the foam seat back core.
The cover should now be loose, so if it feels like it is caught on something, you probably missed an attachment somewhere.
When you get to the headrest posts, simply work the covers around the posts one at a time until the covers are removed. You may need to trim the factory covers slightly, making it easier to slip the top of the headrest post through the hole in the cover.
The re- installation of the seat covers is the reverse of removal. Start with the cover inside out, and align the seams with the edges of the foam. Start to roll the cover down, and attach the hog-rings as you come to them. After you reach the bottom, close the zipper, or reattach your hardback. Reinstall the recovered seat cushion and pan assembly and reattach your plastic hardware.
The bottoms of the headrests are connected with J-hooks. Simply unhook these and roll the headrest cover back to reveal the foam.
To re-install headrests, start with it inside out, and line up the seams to the edges of the foam. Then roll the cover down, and connect the J-hooks.
If you have difficulty rolling the covers over the foam, you can slide the factory foam headrest in a plastic garbage bag, and then put a "shop vac" or regular vacuum cleaner nozzle inside the bag against the foam. Turn on the vacuum and you will compress the foam, making it much easier to cover the headrest. Slide the headrest into the re-upholstered seat, and you're finished with the front leather seats
Rear seat Cushion
The backseat on most vehicles is very easy. Unlike the front buckets, normally the only hardware to remove is the centre armrest and a few clips that hold the lever to release the seat back. The cushion is the easier of the two sections in the backseat. Start with the cushion upside down, and work your way around the cushion sniping hog-rings or unhooking the j-hooks. After you have removed all the attachments around the perimeter of the cushion, fold the cover up over the foam of the cushion to reveal the inserts. Snip the hog-rings for the inserts, and remove the cover.
Re-installation is the reverse of removal. It is best to start with your leather seat cover inside out and hog-ring the inserts first. When you get to the edges, simply fold the cover over the foam. Then, hog-ring the perimeter of the cushion where the factory attachment points are and you're finished
Rear seat Backrest
If applicable, remove the centre armrest from the backrest. A few bolts on the backside of the foam normally hold it on. Remember to note how the hardware fits together.
Some vehicles have a certain order in which washers, bearings, shims, etc. go together to make the armrest fold. After the armrest is removed, remove the factory cloth/leather from the armrest. It is very similar to the headrests, and often easier then the headrests. There should be J-hooks or a zipper on the back of the armrest. Un-hook them and slide the cover off.
To re-install armrest cover, simply start with the cover inside out, line up the seams at the tip of the armrest, and roll the cover over. Hook the new J-hooks together, and set it aside. Now, remove the cover on the backrest. Around the perimeter of the backside of the seat, there are hog-rings that attach the factory cover to the foam. Snip the hog-rings and then roll the cover off the foam to reveal the insert hog-rings. Snip these hog-rings and the cover should fall off of the foam.
If applicable, swap the factory listing wires to your seat cover. Start with the cover inside out, and hog-ring the inserts first. Then roll the cover over the corners and hog-ring the perimeter in the factory locations. Re-install the armrest, and you're finished.
The final step is to put everything back into the car. It is generally easier to install the rear seat first. Be careful when installing the front seats that you don't scrape any plastic or the door panels with the bottom of the seat, as the seat rails are sharp and will damage any leather or vinyl they come in contact with.
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Pigmentation (Colour) Renovation
To reiterate all finished leather that is used as automotive upholstery is multi-stratum; a water-based pigmentation and a thin flexible urethane protective coating.
There is no such thing as a cow with a grey, blue or red hide. The hides are all a neutral tan colour when the hairs are removed, so all pigmented (colour) finished leathers are coated to protects the actual hide
A classic car or modern vehicles leather, if properly cared for should last a life time. How your leather feels (its Patina – literally ‘hand’) tells you more about its condition than anything; it should feel like something between velvet and satin. Supple, inviting and luxurious.
If however it starts to look worm proper renovation is far better than replacement, in all cases except when there is no integrity of the leather to build upon.
Renovation maintains the strength, beauty and utility of leather while protecting against the destructive effects of time and the environment. It also brings new life and resiliency to old or neglected leather that has become cracked or hardened.
There are some great products on available that enable you to restore your old leather relatively easily. Using the product suggestions and methodologies shown will produce a translucent finish that is very similar to an original equipment manufacturers (OEM) finish, which looks natural and blends in so that the finished product is an interior in immaculate condition that also adds to its re-sale value.
With a surface that has been given a finish to match the age of the vehicle, so the natural creases are still there, many repairs done by a ‘smart repair’ give a freshly painted look, which stands out just as much as a worn seat.
Examine the worn or faded spots on the leather surface to decide if the quality of the leather for restoration will have sufficient integrity (see Repair Compound and Mechanical Repair (Sub-patch). Also, any imperfections you see at this stage will be amplified after the pigmentation. These can be removed with a light sanding using 3000 grit finishing paper and follow with a tack cloth and final cleaning.
The urethane pigmentation used for automobile upholstery is classified as a semi-solid permeable membrane, being a thermosetting polymer (elastomers) it remains flexible while retaining its tensile strength, to enable it to expand and contract, following the temperature fluctuations (elasticity) of the substrate. The urethane although very resilient to abrasion wear from entering and exiting the vehicle, by using additives it still maintains its physical properties like flexibility, tactile hand and its patina
A urethanes fibre structure will stretch in all directions with no particular grain or stress pattern. The urethane surface coating will not withstand multi directional stress, however, and when it’s flexed or stretched continuously in the same place the surface coating develops minute cracks. So any pigmentation, fillers or adhesives used must be able to maintain this flexibility, without compromising its structural integrity
Colour change - if you are applying a pigmentation to change the colour of the finished leather; surface preparation (removal of existing pigmentation (colour) is the most important step.
It will be necessary to remove most of the original colour finish without creating thin spots or sanding all the way through the top coat. By correctly preparing the surface and breaking down the original pigmentation, your newly applied pigment will look like an OEM applied translucent finish.
Pigmentation suppliers –
Swisswax Leather Healer - your Porsche seats, upholstery, side moldings and steering wheels start to show signs of wear, even if well taken care of, that spoil one’s overall impression. Swissvax dyes are easy-to-apply using a small sponge and set automatically and permanently, without leaving a heavy layer of pigment as it is often the case with other sprayed-on leather tinting. The leathers fine and natural structure as well as its typical original feel are perfectly preserved. Available in all Porsche standard colours and over 1200 special colours available Refinish Coating - a two part system of premium coatings delivers OEM standards, using the highest-grade water-based coatings to give lasting durability, flexibility and versatility
Leather Magic! ™ - colorants are water-based pigment restoration products used for re-colouring large areas or changing the colour of your leather completely
Leatherworld Technologies – water-based auto leather dye for most marques
Kwazar Mercury Pro - spray bottles are designed specifically for cleaning and detailing professionals. Every pump delivers twice the product onto the surface. High-density Polyethylene (HDPE) is resistant to many different solvents
Plus this sprayer has Viton ® Seals for high temperature and chemically aggressive applications, the spray can be adjusted from fine mist to a constant stream and also has stainless steel (chemical resistant) trigger spring fitted. Sizes available in 0.5 Litre (17 oz.) and 1 Litre (33oz.), available in blue, green, red, and yellow spray tops
1. Surface Preparation
A few days before commencing the actual leather renovation, clean the finished leather surfaces. As a cleaning solution, I use a formula that is used by one of the major tanneries to clean their leather. Mix a solution of 3% detergents that contains a surfactant (P21S Total Auto Wash) 10% isopropyl alcohol (IPA) and the balance distilled water. And then apply Leather Master Soft Touch (formally Vital) this is not a conditioner per se; it softens the finished leather and make it easier to remove the seat covers.
Like all detailing task’s the correct surface preparation prior to the application of the pigmentation (colour) will ensure that it adheres correctly, and has both durability and aesthetics. Use a safe degreaser to ensure any oil and grease free surface (Leather Masters™ Leather Degreaser) this aerosol product is ideal for cleaning as it dissolves the oils and transforms them into a powder that is more absorbent than the leather. This powder is what is wiped off, cleaning and degreasing the leather. Allow the white powder to dry fully. If the powder is drying to a yellow colour, it means that there are still a lot of oils in the leather.
And then use a safe solvent cleaner (Leather Magic DT-152 or Leather Master Color Prep & Cleaner) these chemical is formulated from several types of alcohol and milder based solvents and is used primarily to prepare the surface of leather for repair or pigmentation application. It will remove all dressings, protectants, waxes and oils from the surface, but more importantly, it will strip off the top most layer of the finish, which cleans the surface so that it is receptive to the application of repair and colorant materials. This also creates a permanent bonding of the materials to the leather.
The solvent should be sprayed lightly over the surface, and then by using a medium soft upholstery brush will ensure any ingrained soiling is effectively removed prior to application and to ensure proper product adhesion. Using a cotton terry cloth towel, immediately wipe dry. This will thoroughly remove any foreign matter found on the surface of the leather; mild solvents also work as an excellent de greaser. After letting the solvent dry off for a few hours the area should be lightly sanded over, this will remove any cracks in the surface coating.
To ensure adhesion lightly sand areas to be re-colored by using an abrasive Swisswax Leather Grinding Pad a practical and handy utensil allows you to soften and gently sand down scratches in the leather surface prior to the application of pigmentation, but more importantly, it will strip off the top most layer of the finish, which cleans the surface so that it is receptive to the application of repair and colorant materials. This also creates a permanent bonding of the materials to the leather.
You’ll need to break down approximately 25µ (1 mil) of the surface, this is important so the new leather dye can ‘key’ into the finished leather and look natural. Be consistent in how far you remove the pigmentation, it is not necessary to completely remove the pigmentation that is sitting on the leather surface. Remove dust with a tack rag or damp micro fibre towel.
(DT-173) Overspray Remover is used to remove any water- based colour coat from unwanted areas without causing any damage or discoloration to the area to which it is applied. May also be used to remove Latex or other water-based products; for use on finished leather, vinyl, plastics and cloth.
After the application of pigmentation, add two (thin coats are preferred) or more coats of pigmentation allowing sufficient drying time between each coat. Then apply Swissvax Leather Glaze to ensure that the seating areas are provided with abrasion resistance and durability.
Swisswax Leather Healer
An easy to apply pigment (colour) that sets automatically and permanently, without leaving a heavy layer of pigments as often encountered with other leather tinting leaving the typical original feel of leather perfectly preserved
Certain areas of your vehicles leather interior like seats, upholstery, side mouldings and steering wheels inevitably start to show signs of wear, even if well taken care of, that spoil its overall impression. Often these imperfections are not serious and are simply colour that has worn off or light scratches in the leather surface which can be removed and will disappear with the right application technique and our leather dye.
Swissvax Leather Healer is an easy-to-apply leather dye comprising a high number of super fine pigments combining best results with a minimum thickness of the dye application so that the look and feel of the leather is not affected as it is the case with many other leather dyes. The Swissvax dye is easily applied with a small sponge and sets automatically and permanently. The leathers fine and natural structure as well as its typical original feel are perfectly preserved. Available in 45 standard colours; provide a small leather sample and Swisswax will perfectly match the colour to your interiors leather.
Swisswax Leather Glaze (Colorless)
Use after renovation of finished leather’s pigmentation, this clear top-coat has a dramatic impact on leather, reducing signs of wear. The colorless, clear protective layer provides a matte finish and protects finished leather, keeping it looking 'as new'. It's a must-have product particularly on areas which get the most use, such as steering wheels, leather seats and gear stick knobs.
[Edit: General up-date 05.19.2012]
Edited by TOGWT, 28 June 2012 - 05:06 AM.