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Engine Jumping in First Gear?
kosa - December 14th, 2010 at 11:16 PM

Hey guys

My baja bug is in the wars at the moment.

after a run up mt sugarloaf in Newcastle, i was comming back into town and at the fiirst set of lights i stopped at, i attempted to take off in 1st gear and i got to about 5Km and the whole car jumped violently, quickly i put it in 2nd and the car drove fine.

i later tested it again when i arrived home, the car changes gears fine. but when i go to 1st gear it jumps and shakes the whole car. reverse gear is also fine.so really 0-5Km it's ok but when u start to get above that bang bang bang it jumps again...

any ideas?

im stumped...
gearbox? clutch? engine? what?

any help is appreciated :D

Cheers
Kosa


jsheppard64 - December 15th, 2010 at 01:06 AM

hmm
I'd check engine mounts


vlad01 - December 15th, 2010 at 06:56 AM

SA or irs? could be spring plate or trailing arm bushes. Or any other of the mounts. Check also the frame horn and if you have traction bars (aka kafer bars) check them too.

Oh I might add the CV joints as they can do it.

If all this checks out ok then look at the clutch and/or tranny
(excessive backlash)


beetleboyjeff - December 15th, 2010 at 08:28 AM

Check the Bowden tube on the clutch cable still has a bend in it. If not, that will cause something like that.


waveman1500 - December 15th, 2010 at 01:14 PM

Quote:
Originally posted by beetleboyjeff
Check the Bowden tube on the clutch cable still has a bend in it. If not, that will cause something like that.


I agree with this, sounds like clutch or clutch cable to me. The clutch cable is supposed to have about 1/2" or so of upwards 'bend' to it, which can be adjusted by spacing out the cable outer using washers at the gearbox end. This procedure is detailed in all the manuals and plenty of online sources.


1916baja - December 15th, 2010 at 06:40 PM

That exact thing happened to our buggy years ago, It was the bowden tube. I found if i just reved it up and dumped the clutch it went away :lol:


vw54 - December 15th, 2010 at 06:43 PM

check the engine / gearbox mounts first


vlad01 - December 15th, 2010 at 07:45 PM

this inspired me to look on my vp as it does it extremely violently in 1st when wet or shiny bitumen. its the only rubbers I didn't replace on the car, the
rear upper and lower control arm bushes. lol the whole diff rocks back and forth with hand brake on and rocking the car back and forth.

so yeah check around, it will be something stupid like that.


kosa - December 16th, 2010 at 12:27 PM

Just had a big look all around the engine and gearbox, checked the following,

- Bowden tube (was not cracked and looked newish)

- Engine Mounts (where not cracked or distorted)

- Transmission Mount ( had a massive split in it and was about 1 cm from the edge of the rubber)

i rang up Nymers in belmont and took it down for him to look at and he agreed that it was the transmission mount. but say i had an after market one on it.

its a bright red rubber mount?? anyone know anything about them?? are the heavy duty?? what mount would be the best??

Cheers guy thanks heaps for your help already!!
Kosa


waveman1500 - December 16th, 2010 at 02:43 PM

If you can get any which are made to a decent quality then I would be going for a factory-style rubber mount.


Sides - December 16th, 2010 at 03:01 PM

Sounds like you have a urethane mount in there... they're stiffer than the stock rubber one, so technically heavier duty tho they seem to not last as long and crack up badly. Do a search on "red disc of death" for how urethane steering couplers tend to fail.

I'd be going for a good OE rubber mount... german if you can get it.

:tu:


HappyDaze - December 16th, 2010 at 07:54 PM

After going through similar problems on No.8 Beetle, it is now 'cured'. It could have been any (or all) of the following:-

Front (trans.) mount - now almost solid (rubber bushes) mounted.

Poly-urethane (red) rear mounts crumbled - now solid (steel) mounted.

Trailing arms (spring plates) were flexing and hitting tyres - bolted 25mm square tube to inside of plates.

Frame forks flex - bracing from forks to frame and body ( and now to roll-cage).

No such problems now.

.


kosa - December 16th, 2010 at 09:10 PM

Quote:
Originally posted by Sides
Sounds like you have a urethane mount in there... they're stiffer than the stock rubber one, so technically heavier duty tho they seem to not last as long and crack up badly. Do a search on "red disc of death" for how urethane steering couplers tend to fail.

I'd be going for a good OE rubber mount... German if you can get it.

:tu:


Thats it!! yer its cracked big time... i think im gonna go the OE rubber mount, and invest in some of those transmission brace things u can buy off Classic vw or sharpbuilt. that should give me the extra strength i need.


F me how are they still being sold if that break like that ay... terrible...


kosa - December 16th, 2010 at 09:12 PM

Quote:
Originally posted by HappyDaze
After going through similar problems on No.8 Beetle, it is now 'cured'. It could have been any (or all) of the following:-

Front (trans.) mount - now almost solid (rubber bushes) mounted.

Poly-urethane (red) rear mounts crumbled - now solid (steel) mounted.

Trailing arms (spring plates) were flexing and hitting tyres - bolted 25mm square tube to inside of plates.

Frame forks flex - bracing from forks to frame and body ( and now to roll-cage).

No such problems now.

.


Ouch... that woulda robbed you of your limbs...


HappyDaze - December 17th, 2010 at 06:44 AM

Excepting the roll cage, the mods were done with 'stuff that was laying around'. I consider myself very fortunate, as I am fairly fit, handy with mig & tig, and have plenty of spare time. The 'work' involved in improving my Beetle is a 'labour of love'. You will fix your problem, I'm sure - there has been some sound advice given here.

Cheers, Greg


vlad01 - December 17th, 2010 at 07:14 AM

the urethane rubbers have good squash properties and durability but crap shear and stretch properties. But like anything there is different qualities of urethane rubber.

ever compared nolathane bushes to superpro or k-mac? If you have then you'll know what I am talking about.