Differential Clunk

[Peter Lund, MD]

I feel like a young child asking to hear that scary story again! I have a new Clunk from the rear somewhear. How does one diagnose the dreaded differential clunk again??? Is there a definitive test? What do I need to fix it? Pete Lund __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com [Non-text portions of this message have been removed]

[9001 Engineering (Pty) Ltd]

Diff clunk - I have an MGB and the clunk is not from the diff but from play on the knock-off hub splines. The new ones are in the box. One way to test is to drive @ 100km/h, push in the clutch and then apply brakes fairly strongly. If you hear the clunk, it is the hubs. Andr TC8020 South Africa

----- Original Message ----- From: "Peter Lund, MD" Pgl@prodigy.net> To: mg-tabc@yahoogroups.com> Sent: 11 March 2005 04:24 Subject: [mg-tabc] Differential Clunk > > I feel like a young child asking to hear that scary story again! I have a new Clunk from the rear somewhear. > > How does one diagnose the dreaded differential clunk again??? Is there a definitive test? What do I need to fix it? > > Pete Lund > > __________________________________________________ > Do You Yahoo!? > Tired of spam? Yahoo! Mail has the best spam protection around > http://mail.yahoo.com > > [Non-text portions of this message have been removed] > > > > > Yahoo! Groups Links > > > > > > > >

[David Lodge]

Speaking of which, is there any way of telling when the splines are worn while the whole lot is dismantled; and how do you tell if it's the hub or wheel that's the problem? Regards, David Lodge ----- ORIGINAL MESSAGE ----- From: "9001 Engineering (Pty) Ltd" 9001pty@netactive.co.za> To: mg-tabc@yahoogroups.com,"Peter Lund, MD" Pgl@prodigy.net> Subject: Re: [mg-tabc] Differential Clunk Date: 11.3.2005 - 7:39:09

> > Diff clunk - > > I have an MGB and the clunk is not from the diff but > from play on the > knock-off hub splines. The new ones are in the box. > > One way to test is to drive @ 100km/h, push in the > clutch and then apply > brakes fairly strongly. If you hear the clunk, it is > the hubs. > > Andr > TC8020 > > South Africa > > ----- Original Message ----- > From: "Peter Lund, MD" Pgl@prodigy.net> > To: mg-tabc@yahoogroups.com> > Sent: 11 March 2005 04:24 > Subject: [mg-tabc] Differential Clunk > > > > > > I feel like a young child asking to hear that scary > > story again! I have a > new Clunk from the rear somewhear. > > > > How does one diagnose the dreaded differential clunk > > again??? Is there a > definitive test? What do I need to fix it? > > > > Pete Lund > > > > __________________________________________________ > > Do You Yahoo!? > > Tired of spam? Yahoo! Mail has the best spam > > protection around > > http://mail.yahoo.com > > > > [Non-text portions of this message have been removed] > > > > > > > > > > Yahoo! Groups Links > > > > > > > > > > > > > > > > > > > > > Yahoo! Groups Links > > > > > > > >

-- Akcni unorova nabidka "3 za cenu 1"! Ziskejte VOLNY ADSL 512/128 3GB za cenu 1GB! http://adsl.volny.cz

[Narfman96 - Narfland Studio]

The Dayton Wire Wheel web site once had a chart showing their opinion on how much wear is acceptable on a spline drive wheel. I just checked the site, and the info is no longer there. As I remember the details, you examine the teeth. If the teeth are square, the hub is fine. If the leading edge is partially worn, you can get by for a while yet. More wear will cause the teeth to look a bit like the profile of the Matterhorn Mountain; the leading edge is angled and the trailing edge is vertical. If the trailing edge is angled, replace the hub, it may not hold when brakes are applied. You probably would do well to replace the hub anyway, just for Safety Fast!

----- Original Message ----- From: "David Lodge" archie_ponsonby@post.cz> To: 9001pty@netactive.co.za>; mg-tabc@yahoogroups.com>; Pgl@prodigy.net> Sent: Saturday, March 12, 2005 5:36 PM Subject: Re: [mg-tabc] Differential Clunk Speaking of which, is there any way of telling when the splines are worn while the whole lot is dismantled; and how do you tell if it's the hub or wheel that's the problem? Regards, David Lodge ----- ORIGINAL MESSAGE ----- From: "9001 Engineering (Pty) Ltd" 9001pty@netactive.co.za> To: mg-tabc@yahoogroups.com,"Peter Lund, MD" Pgl@prodigy.net> Subject: Re: [mg-tabc] Differential Clunk Date: 11.3.2005 - 7:39:09 > > Diff clunk - > > I have an MGB and the clunk is not from the diff but > from play on the > knock-off hub splines. The new ones are in the box. > > One way to test is to drive @ 100km/h, push in the > clutch and then apply > brakes fairly strongly. If you hear the clunk, it is > the hubs. > > Andr > TC8020 > > South Africa > > ----- Original Message ----- > From: "Peter Lund, MD" Pgl@prodigy.net> > To: mg-tabc@yahoogroups.com> > Sent: 11 March 2005 04:24 > Subject: [mg-tabc] Differential Clunk > > > > > > I feel like a young child asking to hear that scary > > story again! I have a > new Clunk from the rear somewhear. > > > > How does one diagnose the dreaded differential clunk > > again??? Is there a > definitive test? What do I need to fix it? > > > > Pete Lund > > > > __________________________________________________ > > Do You Yahoo!? > > Tired of spam? Yahoo! Mail has the best spam > > protection around > > http://mail.yahoo.com > > > > [Non-text portions of this message have been removed] > > > > > > > > > > Yahoo! Groups Links > > > > > > > > > > > > > > > > > > > > > Yahoo! Groups Links > > > > > > > > -- Akcni unorova nabidka "3 za cenu 1"! Ziskejte VOLNY ADSL 512/128 3GB za cenu 1GB! http://adsl.volny.cz Yahoo! Groups Links

[Roger Furneaux]

Pete Lund asked:

>I feel like a young child asking to hear that scary story again! I have a >new Clunk from the rear somewhear. >How does one diagnose the dreaded differential clunk again??? Is there a >definitive test? What do I need to fix it?

Well Pete, how long is a piece of string, or more to the point, how fat is your chequebook?? Seriously though, here are a few simple checks you can make. Wheel centres moving on the hubs give only a small click, and you get this every time you reverse out of the garage (which slightly untightens the spinners) then move forward (which tightens them up again). Nothing to worry about. More likely to give a clunk is one (or both!) halfshaft loose in its hub splines. This will only get worse with time, and every quick and dirty solution to the problem has not worked! Years ago splined inserts were available, but new hubs are as cheap as inserts (even if you could still get them) plus the machining, and you will need new shafts anyway. So you are looking at new hubs and shafts, either splined or taper fit, as supplied by Bob Grunau and myself. Splined 95GBP/US$180, taper fit 150GBP/US$285 plus postage from England. Pull rear hubs and inspect: you might also find the hub full of oil, which you can keep in the diff. with my hub nuts & lip seals (25GBP/US$48 a pair.) A rather rare problem is the whole end of the axle casing getting loose: this has the square flange that the brake back-plate is bolted to so there is quite a lot of torque on it. It should be a very tight interference fit in the tube of the casing (which was probably heated to install it) with six rivet-like pegs as back-up. All can get loose,and even fall out (which can lead to loss of diff. oil) so check by jacking up the wheels, then with the handbrake hard on, try to rotate the wheels: if the back-plate moves, you have a problem! If all that checks out OK, start looking at the diff. Bearing break-up usually occurs gradually but if the front thrust bearing allows the pinion to move too close to the crown wheel, one or more teeth could be damaged. Grab the pinion flange with both hands (from underneath, or more easily by lifting the parcel shelf) and see if it moves in-and-out or sideways (should be virtually no movement), also how much it rotates (obviously, the handbrake is on.) A small amount, say 1/4" or just over, is the normal back-lash of the gears. Any more could be excessive back-lash, or the half shafts tuning in the hubs. Now with the rear of the car off the ground, rotate the flange slowly at least six times, feeling for any signs of damaged teeth, indicated by cogging, or tight spots. If in any doubt, it is easy to pull the diff. unit (or "Pumpkin") for closer inspection. All diffs with many years of hard use which still have the original bearings, are on borrowed time: I have lost count of the number I have fitted taper-roller bearings to in the last seven years, including three of the T-Racers here in the UK, without a single failure. While you are looking at the flange, check the four bolts, originally with split-pinned castle nuts: use new HT bolts with Aerotights or Philidas all-metal self-locking nuts. Other bolts to check are the eight holding the axle to the springs: they could be stretched and loose, or the axle mountings broken. Its possible a Hardy Spicer joint is breaking up (how many of us ever grease them?) and also that the gearbox RHS back plate has broken, but that is more obvious as a clunk when you let in the clutch. Happy Hunting! TCRoger, Devon, Olde England PS: I will be giving a seminar on the TA/B/C back axle at the T-Register Rebuild day next week, although it is probably too late now to get a place. I keep in stock every part for these axles, including my latest creation, the new, improved drain plug with magnet!

[joecurto@aol.com]

David get out a hand held wire brush and some solvent, clean splines on both the hub and the wheel and inspect. Usually the early T hubs have decent external splines but bad axle splines ( internal) . the wheels on the other hand wear pretty bad, but with good cleaning you can see where unworn spline ends and wear begins. I also believe that the Moss Motors catalogue shows a picture of spline wear. If splines are pointy and razor sharp then they are worn and putting a new wheel on a worn hub will only destroy the wheel pretty fast. Joe Curto [Non-text portions of this message have been removed]