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MG MGA Front wheel bearing replacement on a MkII BBS discussion at MG-Cars.net
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MG MGA - Front wheel bearing replacement on a MkII
| I've been hearing a slight squeak from the left front wheel lately, so today I jacked it up and found some play (pulling on top/bottom of tire) that isn't present on the right side. I pulled the wheel off, then removed the grease cap and the outer bearings look pretty poor (see photo). When I rock the rotor back and forth, top to bottom, I see play in the wheel bearing race (the gap where the ball bearings lie) which might be due to fact there doesn't seem to be a full set of bearings. So, I'm ready to pull them (both outer and inner) out, inspect and almost certainly replace. I've gone to the archives and also Barney's site and gotten an idea of the overall procedure, but I'm wondering exactly what tools I'll need to make this a straightforward afternoon. Do I need a wheel puller and/or any special tools (I have disk wheels). Also I'm wondering about the final repack and adjustment. The Timken bearing people (http://www.timken.com/industries/automotive/autoaftermarket/techtips/AutoTechTips_Vol1_Issue3.pdf) recommend using a "dial indicator" to check it. Any suggestions and "lessons learned" will be greatly appreciated. - Ken  |
| Ken Doris |
| One other question - any recommended source for new wheel bearings? I'm planning to use Moss parts through LBCarco. - Ken |
| Ken Doris |
| Ken, No special tools are required. In the attached photo (sorry for the blurred picture, I saved the wrong one!)you are looking at the small bearing end of the hub. The bearing races are a slight press fit and must be driven out of the hub. In the photo you will notice two half mood notches 180 degrees apart in the bearing race seat. You use a drift in these notches to drive out the front and rear bearing races. You will also have to drive the new bearing races in the hub. Use a brass drift if you can so as not to damage the new race. Hope this helps and have a good day! John |
| John Progess |
| John - thanks for the advice - I'm now shopping for a brass drift :) BTW I don't see an attached image - can you send it directly to my email account? - Ken |
| Ken Doris |
| First, a wheel bearing noise is not usually described as a squeak. Squeaks that are related to the speed of the wheel turning are usually brake related. Most brakes do squeak some and that is normal. Your bearing picture does not really show any thing. To inspect the bearing you must clean it. That said because the MGAs use ball bearings and not taper roller bearings any play in the wheel is in the bearings as long as the nut is tight. There will always be a little play in MGA front wheel bearings. The way it is set up The nut (14) is tightened against the washer (12) that is tight against the inner race of bearing (10) then to distance piece (5) then through the inner race of bearing (4)to piece (2) that is against the spindle (1). These items are tight against each other so as I said any looseness at the tire is in the bearings. Some looseness is Normal and necessary. The nut, I see no torque spec in this book, is tightened tight then on to the next hole to line up the cotter pin. My guess is over 40 Ft Lbs. Any one have a spec out there? As long as you are tight then on to the next hole you should be OK. To remove the wheel bearings you must first remove the caliper and secure it so it is not hanging on the brake hose. Piece 11 covers the hole through which you remove the cotter pin. Always use a new cotter pin. You can then remove the nut (14) Was it tight? if not that could be you looseness. The hub now just pulls off. A punch (preferably a brass drift) carefully against the distance piece(5) will drive the bearings out. Once out Clean, repack, replace as needed. Use a new seal (3) if possible. Randy  |
| R J Brown |
| Ken, if you don't have one, your best investment will be an MGA shop manual. While Barney's website has a wealth of excellent information not found anywhere else, guidance there and elsewhere usually presumes you've familiarized yourself with the procedure described in the shop manual. RJ is correct. On all MGAs except those with Dunlop brakes there is no adjustment for end float. (This you will find in the shop manual.) The specification for the nut is 40-70 ft.-lb. to accommodate the nearest castellation of the large nut. (Again in the shop manual I have.) Do NOT back off the nut as described in the procedure you referenced for tapered roller bearings. (Again, the shop manual.) Also, do not use tapered roller bearings as a replacement for the stock ball bearings. (Some sellers on Ebay will sell tapered roller bearings and imply they can be used for the MGA.) Appropriately large socket wrenchs that will match up with the exposed surface of the outer race (and fit within the hub without binding), a piece of 2"x4", and hammer are useful to drive the bearing home if you don't have access to a press. Take your time with moderate strikes on alternate sides of the bearing and watch that the bearing is going in straight. Removing and inserting the bearings always produces some wearing on the hub surfaces, especially if they get tilted while being driven in, so bearings shouldn't be removed unless they need to be replaced. For the few bearings involved, just pack them by hand before reinstalling them in the hub. (Invest in a box of nitrile gloves and keep them handy for jobs like this.) A 1/4" thick layer of grease along the inside of the hub should be a sufficient reservior of extra grease. Don't pack the volume completely full or the grease will be forced out the seal and likely spun onto the brakes. Be sure you orient the distance washers in the correct orientation when reassembling. I found that if the cotter pin was fitted with one end bent over the end of the axle that it would interfere with the end grease cap, which then wouldn't seat all the way. I had to use the more common orientation and bend the ends of the cotter pin around the circumference of the nut. (Be sure the length of the ends of the cotter pin will not permit them to enter the bearing if the cotter pin should rotate.) Probably should check the bolts securing the rotor to the hub to be sure they're properly torqued. (40-45 ft.-lb., as I recall.) You'll need another pair of hands to help with this. Steve |
| Steve K |
| OK, I cleaned out the grease and grime and found that the ball bearings were more like oval bearings, with lots of extra bits (remains of small cages for the balls I think) mixed in! So bad that when I removed the cotter pin the nut came off with just my fingers - not exactly 40 ft-lb, eh? I am so fortunate I didn't drive this further. Then again, a testament to the overall design that it managed to keep me and Melon intact for the last 1000 mile round trip to Watkins Glen, including a couple of hot laps of the old course! Thanks for all the advice - I'll pull and replace both sides and probably post more pictures as I go for the archives. One last thing - I do have the shop manual but posted this question since it (the shop manual) only speaks in terms of special tools (e.g. "withdraw the front hub using tool 18G304) and matching tolerances to the thousands when installing the shims! - Ken |
| Ken Doris |
| Ken, What shims? The pushrod MGA with front wheel ball bearings does not need shims. The ball bearings cannot be adjusted. The Twin Cam MGA, which has tapered rollers and a distance piece, uses shims for front wheel bearing adjustment. Mick |
| Mick Anderson |
| I think you are looking at Section KKK in the Workshop Manual, which is for Dunlop disc brake cars, Deluxe models. Refer to earlier Sections K and KK. |
| John DeWolf |
| No adjustment shims on your car. Sounds like just a normal wheel bearing job. Good luck, Randy |
| R J Brown |
| OK, the hub is off, and I'm working on driving out the old bearings. The workshop manual says to use a drift, down from the back of the hub to remove the outer bearing, then remove the spacer and use the drift to remove the inner beariing. Problem, with both inner and outer bearings still in place, there's no place to place a drift or screwdriver except on the inner ring of the bearing because the inner spacer is between them, obscuring the largerer diameter rings of the bearings. It's inner radius doesn't allow access to the half moon notches John Progess mentions - only an angle to drift against the inner ring of the bearing. So, I used a drift against the inner ring of the outer bearing (it was completely shot anyway) and the result was it drove out the inner ring (and the remains of the ball bearings) but still have the larger ring of the outer bearing still in place. Now I don't see a way to drive out the remaining larger radius piece of the outer bearing. What am I missing here? - Ken |
| Ken Doris |
| You have been unlucky. Driving out the inner ring of the outer bearing should have taken the outer ring with it. Obviously your ball bearings were in a very bad condition, but more importantly the ball locating cage must have been broken and unable to keep the balls evenly spaced. If they can all go towards one side the inner ring will come out by itself. With the inner ring and balls out of the way, can you put a puller in the ball groove in the outer ring and pull it out? Mick |
| Mick Anderson |
| You should now be able to push the spacer off to the side enough to get a drift against the outer outer race in the little notches. It is best to use a soft steel drift rather than brass, since brass has a tendency to chip off and get you nowhere. Same on reassembly, since you do not need brass chips in your new bearings. About a 3/8" mild steel rod is perfect and will not harm the races, which are very hard. FRM |
| FR Millmore |
| FRM - I can't get the spacer off to the side enough to get any angle at the edge of the remaining ring of the outer bearing. From what I see, nothing about the arrangement of spacer vs. outer bearing has changed. Mick - to use a puller I assume you mean I need to put the hub back on the axel spindle to get a way to leverage it off - correct? Even with that, I'm thinking where isn't enough space between the spacer and the outer ring to get a puller in there. Much thanks for all the help here... Perhaps I need to seek out a machine shop? - Ken |
| Ken Doris |
| Place the hub outer face downward. Let the inner race spacer drop into the outer bearing outer race. Use a drift on the inner end of the spacer to drive out the outer bearing outer ring. |
| Barney Gaylord |
| Ken, Barney's suggestion should do it, but what I meant was to put the puller claws in the ball grooved track, not to try and get the claws between the spacer and the outer ring. You would not put the hub back on, the threaded bolt of the puller would press on the end of the spacer. Mick |
| Mick Anderson |
| Ken, When you replace your front wheel bearings I suggest that you use high temperature bearing grease. I use Castrol HTB (high temperature bearing) grease. The ball bearings generate very little heat, but the disc brake rotors get very hot and transfer a lot of this heat to the hubs. Mick |
| Mick Anderson |
| Ken- Sorry; I have been influenced by the preceding posts! With the bearings having come apart, it's just like the MGB taper bearing hub. You should be able to displace the spacer such that you can get the slender 3/8 drift down through the center of the spacer to fit in the little cutouts, to drive the outer race of the INNER bearing out. Then the spacer will come out the back, and then you drive the outer/outer outer dere(!) FRM |
| FR Millmore |
| Barney - what role does the spacer play in the hub? What is the downside if I should damage it with the drift (and should I use a brass or steel drift)? - Ken |
| Ken Doris |
| FRM - not enough room to reach the cutouts, but plenty to put a large drift punch on the inside ring of the inner bearing, which was still in good shape. I drove that out, then could use the cutouts to punch out the outer bearing remaining outside race. Here's a picture of the two bearings - inside in good shape, outside, well... Thanks to all !! - Ken  |
| Ken Doris |
| Mick - as for bearing grease, I'm planning to use Mobil 1 synthetic. The list of applications on the can shows wheel bearings first and it claims to be high temp with an operating range from -40 to 350 deg F. That high end is about equal to the 175C rating for Castrol HTB. - Ken |
| Ken Doris |
| The inner race spacer has a couple of rolls. For the MGA with ball bearings, inner and outer race are the same width, and the spacer is same length as distance between shoulders in the hub. With space in place you can tighten the spindle nut securely, and the bearings are all nicely aligned. Ball bearings run with a small amount of internal clearance, so no adjustment is necessary. The mga twin cam (and "Deluxe") and MGB use tapered roller bearings. These have shims to adjust position of the inner race to control running clearance. In all cases the inner race spacer also serves as a spindle stiffener. When you tighten the spindle nut securely the bearing inner races and spacer become one with the spindle, effectively increasing the diameter of the spindle and greatly increasing the bending strength. |
| Barney Gaylord |
This thread was discussed between 30/09/2007 and 07/10/2007
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