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MG MGA - Sealed front wheel bearings?
| A couple of years ago, I was thinking about changing over to tapered bearings. That would have required re-engineering the bearing seal area. I did not move forward on that idea. Now I am thinking along different lines. Has anybody replaced the open bearings with sealed bearings? These do not require greasing and are commonly used on modern vehicles. The 2 numbers I am considering are: 63042RSC3 63062RSC3 or similar units. Although I do not have wire wheels, I would think that this would eliminate any grease finding its way out the inner ends of the wires. Somebody must have done this and can recommend a reliable supplier. Chuck |
| C Schaefer |
| Chuck, Although I have not done anything to my wheels, I have worked on several front wheel drive cars with the sealed bearing system you describe. I personally can see nothing wrong with the idea, and am sure that if you request NTK or Timken bearings, you will get high quality bearings. Good luck and let us know how it turns out. Mike |
| mike parker |
| Chuck, I assume that you are thinking of using sealed ball bearings (not tapered rollers) with the spacer tube between the bearings? Mick |
| Mick Anderson |
| Yes Mick, I am now planning on BALL bearings. Although I see no issue with using the tapered bearings in spite of the "bad press" they have had in the past. My feeling is a slight preload on a tapered bearing (an accepted engineering practice)without the center spacer tube should work fine, although I have not tested it. It would require a slightly thinner spacer behind the inner bearing for the seal to ride upon. Many have, in the past, sugggest the inner spacer tube is required for spindle strength. With a slight preload on the roller bearings, the rotating hub itself should form the strength-adding member. Coming up with the proper radial position of the adjusting nut to align with the hole for the cotter pin could be "tuned" with a shim washer on the outside of the bearings. But I digress, what I am now looking for is rubber-sealed ball bearings that are a drop-in replacement. No rear grease seal would be required because each bearing would contain their own seals. This wheel bearing discussion comes up every year or so. What I am looking for is someone who has made the change to sealed bearings in the past and has had some miles of experience in case I am missing something. Chuck |
| C Schaefer |
| Chuck, I am also digressing, but I think that it needs repeating as some people are reluctant to look up the archives. I have tried tapered rollers on a MGA and found that the preload adds quite a bit to the rolling resistance. But the most important thing is to use the spacer tube with the tapered rollers,and with shims you can lock the hub nut fully tight. The mga twin cam was fitted with tapered rollers as standard, trading off more rolling resistance for stronger side load strength. But the factory retained the the spacer tube with shims and did not consider that the rotating hub gave the required strength to the spindle. See image. Sorry for hijacking your post. I cannot supply details of sealed ball bearings available, but I am sure that any large bearing supplier could match the current bearings. Mick  |
| Mick Anderson |
| I think that if you send a solution off in search of a problem, it will usually find one. |
| Del Rawlins |
| Chuck, I have used sealed front wheel bearings on my mga for about a year or more without any adverse signs and certainly as you suggest no grease spillage onto my wire wheels. |
| J H Cole |
| Hi Chuck I used NSK bearings in my MGA and have had no problems. Ask any bearing supply company for 6304VVCM NS7S404 (Inner - small bearing) and 6306VVCM NS7S409 (outer - large) Hope this helps Brian Woolmer Sydney |
| Brian Woolmer |
| JH and Brian, Thanks for relaying your experience. Did either of you decide to keep the inner hub seal? Or, since the braings are sealed, did you just remove it? Chuck |
| C Schaefer |
| I would grease and reuse the old seal so if in the future someone needed to return to stock the seal surface would not be rusty and pitted. It would serve no other purpose but dirt protection in your application. |
| R J Brown |
| Certainly makes sense to me RJ. Thanks all. Chuck |
| C Schaefer |
| Hi Chuck I replaced the inner seal just the same. If you can buy PBR seals over there the number to get is TC 12610 54.72.8 or your agent might be able to get the right seal based on an equivalent number Cheers Brian |
| Brian Woolmer |
| Chuck, just a comment on the bearing numbers - the C3 designation is I think for a "standard fit" of ball to race tolerance. You might find this gives a bit too much movement at the rim. I used a C2 fit (unsealed bearings) and it was a lot better. |
| A Pearse |
| Not sure that I should butt in on this thread as I have never owned an A. I have owned a B in recent years and currently own a MMM car, a PA. However I cannot resist responding to comments about the use of tapered roller wheel bearings. I am not an engineer but did work for Timken for 40 years. Tapered roller wheel bearings should have 'end play' not preload. The end play should be 3 thou or so. (See the MGB work shop manual) or a Timken reference work if you want it from the horse's mouth. On my PA I use sealed ball bearings with a seal in the original position as well (belt and braces).The hub design is very similar to the A (or more correctly I guess the A is very similar to the P). I have used them for 2 years and they have worked well for me. I also use a sealed ball bearing in the rear hubs. This has the added advantage of improving the defences against oil getting onto the brake shoes. I will now get back to the MMM and VSCC forums and leave you guys in peace. Peter |
| Peter Scott |
| Peter, preloading varies by application. While I agree that in most cases wheel bearings are not preloaded. In the rear diff it is very common. The pinion bearings are preloaded untill you reach a required torque value to rotate the pinion. The carrier bearings are shimmed until there is no play and then you add another spacer of .002 or so to both sides to preload the bearings. |
| J Heisenfeldt |
| Peter, feel free to add to the conversation. You are welcome any time. From what I have read, I believe that Timken, and others, recommends a preload. The problem being that a slight preload is preferred but a bit more than slight is worse than a bit of slop. (My choice of terminology). In some high speed applications, the heat generated can make the preload worse. Here is the Timken reference I found: http://www.timken.com/en-us/solutions/automotive/aftermarket/heavyduty/techtips/Documents/Vol6No3.pdf As for your use and testimony of the sealed roller bearings, this is much appreciated. I have purchased my bearings and will be installing them in the next week or so. Thanks for everybody's input. Chuck |
| C Schaefer |
| Chuck You can not compare the preload on a pinion bearing which is almost floating in EP oil. The oil is providing a constant lubrication, dissipating heat and removing wear particles. On the sealed bearing little or no preload is used to allow the inbuilt lub to do its job. Some machinery uses preloaded sealed bearings for accuracy but only in very slow moving items. Denis |
| DENIS4 |
| Denis, rest assured that I am not planning on preloading ball bearings. The discussion of preload was relating to the possible use of tapered roller bearings. Thanks for your concern. Chuck |
| C Schaefer |
| Chuck Sealed bearings work fine. I have used them front and rear om my L2 and driven quite a few miles. I also use them on the MMM vertical camshaft drive which is a notorious leakage place. Go for it. All the best from another non MGA M.G. man Sven |
| SO Sven |
| Chuck The Timken reference confirms that the longest bearing life occurs with a very small preload but the article has a significant caveat: "When truck and trailer wheel ends are adjusted in a controlled manner, slight preload can be beneficial to the success of long wheel end life. Slight preload can improve bearing, seal and tire life, but only if the entire process is in control. “In control” means that you actually know the bearing setting process will result in a consistent bearing setting range." Unfortunately in the case of older cars the process is not under sufficient control. And as you can see from the graph bearing life drops dramatically if there is too much prelaod. So the article which is relevant to our cars is http://www.timken.com/en-us/solutions/automotive/aftermarket/lightduty/TechTips/Documents/TimkenTT_EN_Vol2_Iss1.pdf This stresses the need for end play. The end play should be achieved by shimming the beariing spacer so that when the hub nut is tightened to the correct torque there is 3 thou or so end-play. The exact procedure is described in the MGB workshop manual. Peter |
| Peter Scott |
| Peter, and others, I have read this caveat and more on Timkens and other's websites. I am very confident in my skills and my tools. I am capable of setting preload as repeatable as the best of shops.... really I am. And I am capable of reading and interpreting bearing data sheets to determine the proper preload requirements for application in our cars. That is not the issue. This thread was originally about ball bearings and I took it off-base with a very short dissertation about the use (and lack of need) for the distance tube as used in the MGA ball bearing setup and the MGB roller bearing setup. My feeling was, and remains, that by providing the accepted practice of preload (under controlled conditions)this would cause the rotating hub to strengthen the axle stub. Many here have discussed in the past that the stub itself is not near strong enough to support the car. Further, the distance tube provides this extra strength. While this may be true to some extent, I believe that the primary reason for the distance tube is to prevent the inner races of both inner and outer bearings from rotating on the stub axle and to prevent an axial load to the roller bearings themselves. They are not designed for axial loads as are the rear bearings. I have toyed with the idea of changing to tapered roller bearings in the past and still believe that this can be done reilably with some added benefit. However, I will not go in that direction, so all of this is moot. Sealed ball bearings are the way I am going even if it is not how the car was designed. This will be my last post in this thread. Hopefully, someday somebody |
| C Schaefer |
| Sorry sent too soon. Hopefully, someday somebody will implement the roller bearing without the distance tube (with a controlled preload and prove one way or the other whether this ia a viable redesign. Sorry fot he rant, Cheers, Chuck |
| C Schaefer |
| Dunno bout you MGA and MGB types ;-) In the Spridget world a number of us have done the tapered roller bearing conversion, some with the distance piece and some without. I opted to do it without. Timken recommended eliminating the distance piece because their bearings really are not designed for it. The Spridget stub axle is as hefty as that of some significantly heavier Triumphs that do not use the distance piece. According to Timken, although there are some trucks that use a distance piece in a similar fashion, the amount of torque necessary to accomplish ANY strengthening of the stub axle greatly exceeds the capacity of the threads on the stub axle. Anyhow, I have 30,000 miles or so on the tapered wheel bearings in my 1972 midget, including a trip to the Grand Canyon and many autocrosses with no ill effects. David "no bearing on the matter" Lieb |
| David Lieb |
| Chuck I am not for one moment doubting your ability to adjust bearings. However technology has moved on significantly during the past 50 years. Today very fine settings can reliably be made and maintained. However fifty years ago designs were not so capable. The bearing application engineers spec for the MGB hub, which is very similar to the MGA hub but with TRBs rather than ball bearings, provides for 2/4 thou endplay with a spacer clamped between the two inner races with a torque of 40/70 ft lbs. So a small amount of endplay was specified by the designers and does work. From my experince over many years this also gives long bearing life. No doubt other settings can also work. Now back to the new floor boards for my PA. Have fun, Peter |
| Peter Scott |
| Timken is likely refering to the fact that almost all front wheel drive cars and many 4x4 trucks use a front wheel bearing that consists of a one piece bearing race with a tapered roller bearing in each end and a spacer between the inner races to control the bearing preload. Even the front wheel bearings on my 97 rear drive car uses this system, I couldn't buy front wheel bearings but only a complete front hub, you put it on the stub axle and torque the nut to 150 ft lbs. Harley Davidson has used also used a bearing setup like this for the crankshaft output bearing on their bikes since 1955. |
| J Heisenfeldt |
This thread was discussed between 14/04/2008 and 28/04/2008
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