The commonest cause of damage is the installation
A correctly designed seal lasts a long time — provided it reaches the bore undamaged and the sealing lip does not fold over as it is pushed on. The following points come from our installation instructions.
The installation, from start to finish
The sequence for SOA and DOA, filmed in our own production. No sound — the movements speak for themselves.
Installing a VR seal
The complete installation sequence for designs SOA and DOA, filmed in our own production. The video has no sound track.
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What the video shows
- Which tools have to be laid out before the first move.
- How the installation mandrel is placed — and where the force very much does not belong.
- How the sealing lip is guided over groove and edge without folding over.
- How to tell, after pressing in, that the ring is seated flat.
The details with dimensions and tolerances are further down this page. The video does not replace them — it shows the sequence of movements that a drawing captures badly.
Before the seal is touched
Before installation
- Check the position of the sealing lip in relation to the medium to be sealed, and the installation direction — see the drawings of the designs.
- Check that the housing bore is clean.
- Clean the shaft and oil it lightly with mineral oil.
- Spray the outside of the seal with isopropanol, a 70 per cent solution.
- Chamfer housing and shaft 1 to 2 mm at 30° — free from burrs.
- Cover sharp edges and corners; tape over grooves, for example.
- With double lip seals, fill the grease chamber — more on this below.
Six things that must not happen
- Sharp edges on the tool or the workpiece
- Dirt
- Metal chips
- Residues of molding sand
- Contaminated assembly grease or oil
- Uncovered grooves and slots
Every one of these leaves a notch in the sealing lip. It often only becomes visible weeks later as a leak — and then it looks like a product defect.
The force belongs on the outer casing
- For installation parallel to the axis, use an installation mandrel on a press fixture. If the seal has to sit deep inside the housing, the mandrel is mandatory.
- Press the seal into the housing bore by its outer casing, straight and without tilting — using a mandrel of about D2 − 0.5 mm or a disc.
- If the housing bore has no chamfer, or only a slight one, place a tapered centring ring against the bore — running from D2 + 0.5 mm to D2 H8 — and press the seal in through it.
- Observe the installation depths t1 and t2 so that the ring seats flat.
- Never apply pressure to the inside, and therefore to the sealing lip.
- Do not strike the seal with a hammer.
The housing bore needs a lead-in chamfer of at least 15°, otherwise the seal is not guided in and the diaphragm can shear off. The dimensions are in the Design guidelines.
Do you need an installation fixture? Talk to us — we will build one to suit your sealing point.
Pushing on without folding the lip over
Guiding the shaft through the seal
- Guide the shaft through the seal with a slight turning movement.
- The taper or assembly sleeve must match the design: outside diameter D + 1.0 mm in range I, D + 0.5 mm in range II.
- If the sealing lips face against the direction of installation, they must not fold over or become trapped between shaft and metal ring. If in doubt, push the shaft back with a slight turning movement so that the lips spring back, and only then continue.
- After passing it through, check whether the shaft has been damaged by contact with the metal support bodies.
If the shaft is already fitted
- Push the seal over the shaft with a slight turning movement.
- Make sure the support bodies damage neither the shaft nor the running surface.
- Once the seal has been pushed up to the housing bore, press on the rim with a thrust ring and press it in.
After assembly: The shaft must turn freely. Check this in both directions. Seals fitted askew do not seal.
The installation process in six steps
- Prepare. Fill the grease chamber to about two thirds, check the lip position, check that the housing bore is clean, clean the shaft and oil it lightly with mineral oil, and spray the outside of the seal with isopropanol.
- Taper. If required, place the taper over the shaft journal.
- Push on. Push the seal onto the shaft, turning it slightly as you go.
- Check the seating. Check that the sealing lip is seated cleanly.
- Press in. Press the seal into the housing bore parallel to the axis using suitable aids.
- Check. Turn the shaft in both directions. It must run freely.
Grease and the grease chamber
Against grease, the conditions for carrying away frictional heat are less favorable than against liquid media.
- With grease lubrication, restrict the surface speed by about 50 %. If that figure is exceeded, changing to oil lubrication should be considered.
- For grease-lubricated, slow-running shafts, the bearing manufacturers recommend filling the space as completely as possible.
- With poorly lubricating media such as water or washing liquor, the sealing lip needs a lubricant supply of its own — here we recommend VR double lip seals with a filled grease chamber.
- Watch the chemical compatibility of grease and elastomer.
| Item | Designation | Application |
|---|---|---|
| 89801 | LM AL 200-2, NLGI 2 | Food applications, NSF/H1 approval |
| 89802 | Li 200/2 EP, NLGI 2 | NBR (-1) and HNBR (-C5) |
| 89803 | Syn HT 100-2, NLGI 2 | High-performance grease for HNBR (-C5) at the limit and FKM (-2, -C2) |
The greases are available in all standard commercial pack sizes.
Until installation
Elastomers age even when not in service. It shows as cracking and a surface that turns tacky, and it can be measured as hardening or softening and a loss of elastic properties.
The store must be cool, dry, clean and ventilated. About 15 °C and around 65 % relative humidity are the guide values.
- Store cool, dry and free from dust
- Protect from direct sunlight and UV light
- No ozone-generating electrical equipment in the store — printers included
- No solvents or outgassing substances in the same room
- Do not store under tension, compression or deformation
- Leave in the original packaging
Every design, material and size in one PDF
60 pages of design know-how: pressure and p-v diagrams, design guidelines, the elastomer overview and the complete size table with 541 sizes. You receive the link by e-mail straight away.
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