Lot of interest recently in firming up the dogbone mount, with the resultant improvement in handling, cleaner gear changes and reducing wheel hop, etc. Jabbasport offers their (by all accounts) superbly engineered complete mount as a direct fit-in.

Downsides of a firmer dogbone mount include added vibration while waiting in traffic, with resultant unhappy SWMBO. This does settle with time though (I mean the vibration, not SWMBO)…

After an Internet search, I came across several references to DIY filling of the existing mounts with polyurethane, a flexible but reasonably hard rubber.

Basically it is similar in prep to epoxy glue. You mix two liquids together that react. Looks and pours like motor oil. You can pour it into the mount and after it cures you are left with a firm rubber.

Devcon Flexane is one that has been mentioned favorably several times so I went with this. It’s available from Lawson in the UK for about 33 quid for 500g – which is enough for about five filled mounts (GB anyone?) link: Devcon Flexane Liquid Urethanes - Lawson HIS - UK

It is available in three hardness levels (the units are referred to as “Shore A Durometer” numbers). Higher is harder. For an idea, an eraser is about 42 , regular silicone sealant is about 30-45 Shore and a bowling ball is pretty much off the scale….

The common mistake is to make the mount too hard – some people have used 90 Shore polyurethane and have regretted this and been forced to drill holes in the filled mount to drop the stiffness.

The Devcon Flexane stuff is available in three levels of hardness, Shore 60, 80 and 94. I wanted to go with the 60, as I run a SMF and don’t want too much vibration, but all I could find locally was the 80 (which actually cures to a shore A hardness of 87).

Steps:

• Remove the OEM dogbone – just two bolts:
  
• Clean it carefully – I used hot water and washing up liquid while scrubbing with SWMBO’s toothbrush (!!). Scraped it afterwards with a sharp blade to reveal 'new-looking' rubber. Not only to remove any debris but also to make sure that any mould release agent used in initial manufacture is removed.
  
• Tape up one side of the Dogbone and place it upside down.
  
• Mix up a measured quantity of the poly (100cc was the perfect amount = 1/5 of the total can). If you have an electronic balance you can mix it pretty easily, otherwise you have to dump all the hardener into the resin, which wastes a lot of stuff.
  
• Pour into the upside down dogbone and allow to fully cure for a full 3-7 days (!!)before re-fitting to the car.
  
• Fit it back in place – I intend to coat the bolts with blue loctite and torque them to spec:

Will let you know how this stands up to use and abuse after a few weeks! My console is out as I had a spot of bother with a bolt breaking off while removing the OEM bushes. It's been removed and re-threaded and I hope to have it all back together soon enough.

May well be too stiff but I’m almost always alone in the car and SWMBO is pretty tolerant (NOT!)…(Also I'm not worried about having to put in a few holes with the drill away from the OEM bits....)

Does not look likely to come out, as the poly fully surrounds the OEM center and the rubber has been well abraded allowing it to stick. Also, it’s been left to fully cure to make sure that it doesn’t deform and come out. The properties sheet indicates a lot of ability to stretch and return to normal….

If I had a choice, I would have gone with the Shore A 60 stuff – deffo be softer/ less hard-core (no pun intended)…Oh well...

I wonder if a similar approach can be used to stiffen OEM console bushes while they are still in place without disturbing anything. Would need a clever use of tape/ silicone grease/plasticine and a dab hand at pouring, but it may be an idea….

The poly is really neat stuff - with a little imagination it can be used for a lot of DIY things - my 'helper' mate who has years of mechanical experience in the aircraft industry was quite wowed by it.....

Most posts I’ve seen about recommend against any stiffening of the transmission mounts btw…

Cheers:thumbup:

Bas

That's an interesting mod & a good "how to" Basil, I'll be interested to hear what you think of the results once you have run it for a bit ?

That's an interesting mod & a good "how to" Basil, I'll be interested to hear what you think of the results once you have run it for a bit ?

Thanks for your comments -will let you know for sure mate after a few weeks..

Should I also ask SWMBO's opinion for the record?

Thanks for your comments -will let you know for sure mate after a few weeks..

Should I also ask SWMBO's opinion for the record?

Yeah, as the Furby in this household belongs to SWMBO best get a female point of view as well to be on the safe side ! :thumbup:

another pikey mod from bas,keep it up mate you are a pioneer,this one comes a little too late for me though,i fitted my jabba dog bone mount last weekend:rofl:

The RAF used this stuff to coat the spent ammo bays on the Tornados. It's amazing stuff and really effective if used as a coating (This stuff will deflect direct hammer blows with little or no visable damage).

I once coated my air rifle stock in it resulting in a VERY hardwearing black coating.

So did you nicely clean up and put SWMBO's toothbrush back in the bathroom?

Nice work as ever BAS.

Lawsons aren't too far from me I sometimes buy tools from them if I want draper items.

So did you nicely clean up and put SWMBO's toothbrush back in the bathroom?

Actually, I just kinda put it back - she did remark that the toothpaste tasted strange for a few days...

Basil, any pictures here of your car ?

Basil, any pictures here of your car ?

only one - BRISKODA - The Skoda Forum and Community

need to do a proper page on member's cars one of these days....

Interesting - I replaced mine not so long back as my gearchange felt all slack and I was trying to cure a knocking (which turned out to be the gearbox mount lube thingy in the end).

The old one wasn't that bad really, just a bit soft. Then again my car is standard and so there's not that much grunt going through it. My new one came with the bracket though too and so pulling the old one off may be easier by removing the 3 gearbox bolts too rather than the horizontal one due to access.

http://www.briskoda.net/forums/technical-guides/changing-fabia-vrs-dogbone-mount/80462/

Well initial results so far:

First start-up and the whole cabin was shuddering! First thought was "what the F have I done!?". :eek:

Vibrating went away completely above 1.5K rpm tho'....

Right off upped the idle to 1 K rpm which helped a lot...

Has started to settle nicely after 50 km driving only - only a really noticeable vibration sat waiting at traffic lights, etc.

Will continue to watch and how it settles in further, but it's already at the (just) liveable level now....

Need a proper wheel alignment before I can play with it though....

Interesting stuff

Steve

well i have now covered 500 miles with my jabba mount on and its showing no signs of settling down yet,the vibrations are bad still:D

Would have been far better if I had been able to get the Flexane 60 stuff I feel, but still early days yet.....

see this interesting link with a test of DIY mounts - good discussion and also a solution for reducing stiffness in a too-hard modded mount towards the bottom of the page: U12 Pintara Custom Polyurethane Engine Mount

Could the mount not just be stiffened incertain places like the console bushes?

If the part in red was stiffend this would reduce the movement inline with the car?

The OEM part has spaces of about 2mm between the central 'diamond' shape and the peripery. This allows vibration, but also some movement.

An ideal but not very easy way to do it would be to copy the OEM design perfectly in far stiffer material I would imagine...

i agree with Skudmissile , maybe just fill the area at the front of the large bush , so as to still allow movement to some degree lessening the vibration

i wish i hadn't thrown the spare one i had away now :(

The movement would likely eventually tear away the poly tbh. The engine pulls and pushes so probably just reinforcing the OEM design would be best... Perhaps by putting in a plasticine 'dam' you could fill up everything except the 2 OEM gaps in the front and back.

Thing is tho' - I'm happy with my DIY setup atm - it's quietened down a lot, and this after only about 100 miles... Will continue to evaluate it as time goes on....

Nice work there Basil, saved yourself over £100 on the Vibra technic mount too

Cant believe yours has softened up so quick, guess it helps having all that power going through it but are you sure its all still in one piece down there?

Mine is off the car for now but it'll go back on at some point, if only someone could tell me how to up them idle revs?

VK

Hhhhooooowwwwssss yyyooouuuurrrrrsss nnnnow iiiittttss bbbbbbeeeeen onnnnn aaaaa whhhhhiiillle?????

Gonna wait a bit longer to inspect the mount itself - it still has a bit of a rumbly vibe at idle, but really not bad now. It's still there for sure....

To adjust the idle: Ross-Tech: VAG-COM: TDI VAG-COM Info

Anyone up for doing this with the shore 60? If we only need a bit then surely we could buy it and share/pass it on