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MG Midget and Sprite Technical - Odd - Intermittent - Vibration

I have a vibration that starts at about 45 MPH. I can fell it in the steering wheel, the seat and a little in the gear shift I suppose. Now the odd part, this dose not happen all the time. The vibration usually starts, at about 45 MPH, I can slow down to about 25/30 MPH and speed back up to 45 MPH and the vibration (sometimes) stops or if I stop and get back up to speed it will (sometimes) not vibrate at all to speeds well above 45 MPH. The ride is really smooth when it's not vibrating. I can still drive when it's vibrating it's just annoying. The wheels are straight and balanced as is the drive shaft and the tires are good. Any ideas?
('73 midget)
Jon Saylor

Propshaft?

Doesn't take long to check the UJs and bolts.

A
Anthony Cutler

If you're feeling it in the steering wheel, I'd check the front wheel bearings.

Also, I had a front brake caliper stick from time to time & caused a similar intermittant problem like you describing.

Good Luck,
Dave :)
Dave Rhine ('78 1500)

the most probable issues will be 1 of 2 problems

1 bad wheel bearings ... you need to really hope so.

2. the inner tie rod ball joint is going bad... thats a night mare...Im not to knowledgeable about the later model rack like you have... on the older one it will wear in the ball cap area, and just needs shimmed or the cap ground down... you wont need the shafts even tho wheel shops will say you do, just the minor parts ... to put back togather

to check which is the problem

Jack the front off up with wheels off the ground. keep wheels pointed straight,

1.. grab the wheel at 12 and 6 and give it a good shake...if there is movement its wheel bearings...dont be fooled by New bearings there are some real junk out there...if they are bad you may want to consider the new 40 degree angular bearings... of which you dont want the uber expensive pidolite casings but the brass casing with a friendlier price tag....if so let me know And Ill get you the code numbers for the bearing numbers you need.

next grab the wheel at 3 and 9 and give it a good shake... if movement then its tie rod ends or inner ball joint ... by giggling a bit you maybe able to see where th play is comming from by following the steering arm back into the rubber boot

repeat on the other side

Prop
Prop

wow, prop, hats off,

Diagnose by laughter

Pete (Giggling) Moore :P
PeterJMoore

>>>>>you wont need the shafts even tho wheel shops will say you do, just the minor parts ... to put back togather<<<<<<

yeah that will be a fun debate at the wheel shop... "but prop said I dont need innner tie rod shafts" LOL HAHAHA

what I meant to say is you wont need NEW ones, but yes you still need them.
Prop

Thanks, I will check for all of your suggestions and I'll let you know what I find.
Jon Saylor

Pete, your giggling made me chuckle...

Prop, when you say minor parts, do you mean minor parts or Minor parts?
Willem vd Veer

Jon. Do you have wire wheels? If so have they been balanced correctly, does you tyre bay have the right adaptor for balancing wire wheels?

Bernie.
b higginson

LOl.

how about meager parts... as in 16, 17a, 19, 20 and 22

these parts seem to tear up and get distroyed when removing...at least when I do it

the early rack ended mid year of 71, and the later model rack (triunph) started in mid 71 an ended with the last car off the line

Its also vary similar to the rack for the MGA... so chicagoland MG have a great on-line vid rebuilding the mga rack.

whatever you do dont confuse this as a walk in the park, IT will b a challange esp. breaking the female cup from the male cap holder... Ill pray for you if you have to go that direction.


Prop
Prop

Bernie:
I have stock rostyle wheels.

Prop:
I do have a spare and complete rack. Maybe I should just rebuild that one and install it even if the one that's in the Midget is OK.
I'll be going through the front supention this week end.
Jon Saylor

Jon -

You said your wheels were balanced, which might make my comment irrelevant. But I wonder if there are still slight imbalances that are usually too small to feel, until a couple of wheels rotate to the point that the imbalances are in phase, so to speak, and you then feel a combination of the two. Just a thought... I like to address the simple things first, rather than launch into a full restoration just to cure a rattle. ;-)

So with that in mind, why don't you just move your tires to different wheels and see if that cures it. It may make things worse, but at least you'd know that balance - or a combination of minor imbalances - was the issue.

Cheers,

-:G:-
Gryf Ketcherside

Rostyles are very difficult to balance. It would help no end to have them balanced on the hub if possible
Nick Sayle

Rostyles MUST be centred on the lugholes. The centre hole isn't centred precisely.
If your tyreshop can't centre on the lugholes find one that can, otherwise it is hopeless. Often French car specialist have the proper balancing equipment.
Willem vd Veer

And keep in mind that Rostyles can distort (like mine) at the lugholes, with the holes/wheel center pulling in after years of tightening and over-tightening, and causing the studs to bend inwards slightly. All of which can't help much when it comes to balancing...

-:G:-
Gryf Ketcherside

I checked all that was suggested here and found nothing wrong so I now suspect the Rostyles not being balanced properly as some of you posted. There is a good (old school) tire shop here in town so I'm going to have them balance them and see if that's the problem.
Thanks for all of your posts.
Jon Saylor

You bet, John - let us know how it goes.

-:G:-
Gryf Ketcherside

This thread was discussed between 08/06/2010 and 15/06/2010

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