Section : Gearbox

"strap Type Propshaft" 

Posted By : Flemming Jensen, 14-Jun-2006, 09:15pm

• "strap Type Propshaft" 

  Posted By : Chris Taylor, 14-Jun-2006, 09:55pm

  I'm not exactly sure, but I think the general idea was to provide a small amount of longitudinal flexibility without the trouble or expense of splines. It MAY also impart a small amount of cushioning in the driveline, in a rotational sense.

  • "strap Type Propshaft" 

    Posted By : Flemming Jensen, 15-Jun-2006, 08:12am

    Hi
    
    and thanks for the answer....
    
    It is my impression that the strap type prop includes a splined connections too.
    
    regards Flemming

    • "strap Type Propshaft" 

      Posted By : Dan Owen, 15-Jun-2006, 10:56am

      Got a couple in the shed. I'll have a look later & see if I can figure it out!

      • "strap Type Propshaft" 

        Posted By : Flemming Jensen, 17-Jun-2006, 08:22am

        hi
        
        I have an additional question:
        
        In order to determine if the strapped part of the prop are maiking noise; I wil disconnect it from the diff only. Is that possible; to support it, disconnected from the diff and leave it attached to the gearbox ?
        
        best regards Flemming

        • "strap Type Propshaft" 

          Posted By : Chris Taylor, 17-Jun-2006, 10:55am

          NOT recommended. There is nothing to restrain the end of the shaft, so it will flail around and could wreck the chassis rails, or floorpan.
          The shaft as such will not create noise (unless straps are loose or broken) but if it is out of balance it will tend to cause vibration at speed which "sounds like a noise" if you get my drift!

          • "strap Type Propshaft" 

            Posted By : Mark Powell, 17-Jun-2006, 12:42pm

            Hi, I have dismantled a strap type shaft before and found that there can be play where the yoke shaft inserts to the main prop tube. There should be an 'O' ring on this shaft and it usually self-distructs! Clean it all up and re-assemble with a new 'O' ring. This has improved things for me before! Mark.

          • "strap Type Propshaft" 

            Posted By : Flemming Jensen, 17-Jun-2006, 07:28pm

            sorry about my bad English...
            
            I think you get me wrong there Chris. I will not run the engine with the prop disconnected.
            I will rotate the rear wheels - one by one - by hand instead.
            You see, with the prop attached I can recreate the noise by hand. Disconneting the prop will provide a good way to determine whether the noise is diff or prop related. I am quite sure it is not the UJ's.
            Does that make sense ?
            So my question is merely is at all possible to disconnect the prop/diif connection without first disconnectiong the prop/gear box connection. The manuals suggest to do the front first. And I will only to the rear. Hope you understand what I mean.
            
            
            best regards Flemming

            • "strap Type Propshaft" 

              Posted By : Chris Taylor, 17-Jun-2006, 10:15pm

              Ah, now I do understand. If you can actually recreate the noise by hand, then I would tend to agree that the problem is less likely to be u/j's.
              Yes, of course you can disconnect the propshaft at either end first. To ensure that the diff is completely free to rotate, you may need to drop the shaft down clear of the input flange. You may also need to loosen the gearbox and/or engine mountings to allow the engine/box/propshaft to move forward slightly to allow the propshaft to be quite free from the diff. Some Heralds had a tie bar between the gearbox and rear mounting plate to resist forward motion of the engine under braking. Loosen this right off if you have one.

              • "strap Type Propshaft" 

                Posted By : Flemming Jensen, 19-Jun-2006, 07:25pm

                "You may also need to loosen the gearbox and/or engine mountings to allow the engine/box/propshaft to move forward slightly to allow the propshaft to be quite free from the diff."
                
                right you are. I did disconnect the prop from the diff; but didn't have the time to loosen the mountings. And it was most needed. The propflange was actually quite hard stemmed against the diff ditto. So I didn't determine whether the prop/diff connection makes noise. To bad.
                
                I did discover some potentially abnormalities though - so the work wasn't completely wasted - which you might help me sort out - with the noise issue in mind. See alsoattached picture.
                
                1: the grease nipple was NOT removed from the UJ
                2: the strappes was bended backwards - and that is was they are supposed to do, taking up asial play - reflecting the rather hard pressure from the prop-gearbox-engine, mentioned before.
                
                any comments ?
                
                best regards Flemming
                
                PS: I have a spare strap-type prop which has not been on the road for 25 years. When it was it didn't make any noise. Would you recommend to fit it right away with no maintenance ? I ask, because it seems to be next to impossible/affordable to have a prop rebalanced in Denmark.

                 

                
                
                "strap Type Propshaft"

                 

                • "strap Type Propshaft" 

                  Posted By : Chris Taylor, 19-Jun-2006, 09:21pm

                  Depending on how much time you've got available, it wouldn't do any harm to try swapping propshafts. Apart from the potential need to rebalance, I would suggest replacing the u/js before refitting, but it's probably better NOT to do so at this stage. However, if you can regrease them, (ie if there is a grease nipple, pump full of grease. If there is not grease nipple but there is a blanking screw, take the screw out and insert the nipple (off your current proprshaft if need be) and pump full of grease.) If the u/js are "sealed for lfe", then just hope the existing grease has not dried out.
                  
                  The straps on your shaft do seem to be under some pressure. I recommend loosening off any gearbox-chassis tie rod, and moving the engine forward a little to release this pressure. 10mm should be enough. (just make sure your cooling fan is not too close to the radiator, but you should have loads of space.

                  • "strap Type Propshaft" 

                    Posted By : Flemming Jensen, 20-Jun-2006, 08:05am

                    hi Chris and thanks for the udefull info. I have an additional question though:
                    
                    you wrote:
                    "The straps on your shaft do seem to be under some pressure. I recommend loosening off any gearbox-chassis tie rod, and moving the engine forward a little to release this pressure. 10mm should be enough. (just make sure your cooling fan is not too close to the radiator, but you should have loads of space."
                    
                    Is the engine - when loosened from it's mounts including box and tie rod and the prop disconnected from the diff - moovable by hand or do I need a "three foot". Any tips most welcome.
                    Furthermore, won't the engine settle back in "old" possition when the mount's are retightened ?
                    
                    best regards Flemming

                    • "strap Type Propshaft" 

                      Posted By : Chris Taylor, 20-Jun-2006, 04:28pm

                      The top of the front mountings (where the "stud" of the engine mounting goes throughthe engine front plate) is in a slot in the engine front plate, and the rear gear box mount is bolted through slots in the mounting plate bolted to the chassis. That means that the engine will not "sprng back" to where it was. You need to loosen off the single big nut on the TOP of each engine mount, and the gearbox rear mounting, as well as any gearbox tie rod. Then you can try "wriggling" the engine forward. (Rocking it from side to side may help. If that does not move it, then you may need some form of lever to move it forwards. You could also try taking some of the engine weight on a trolley jack to assist the process.
                      If you don't take the nuts right off the mountings, then you cannot move the engine too far. You may need to repeat this process slightly when refitting the propshaft to get the optimum position.
                      The exhaust pipe will try to resist movement slightly, but it should be able to be sprung 10mm or so on its mountings. I would try to avoid loosening exhaust joints for the minimal movement required.

                      • "strap Type Propshaft" 

                        Posted By : Flemming Jensen, 09-Jul-2006, 10:49am

                        hi Chris and others
                        
                        I did succeed in changing the propshaft with the one from my 20 years off road Herald 13/60 Sedan to my Estate. The swap was undertaken because of heavy noise apparently from the prop/diff connection. With the "new" propshaft mounted the noise did almost disappear - for a while, sigh. Now, after 300 miles the noise is back.
                        The noise now is only noticeable under acceleration. The noise before was noticeable both under acceleration and free wheeling.
                        On both props I could feel a very small movement in the one of the UJ's.
                        The engine might be a bit out of lining with the diif. You see, when I put back the gearbox cover I noticed that the gearstick hole in the cover was 5-10 mm out of center with the gearstick. This might illustrate the fact that I was only capable of moving the right site of the engine 5 mm. Which immediately took the pressure of the propshaft, so I could move it. The left site was not movable. At the time I thought it indicated a misalignment from the very beginning. You see, the car has had prop shaft UJ's and engine mountings replaced only some two years ago by the former owner.
                        This leads to speculations whether the noise is related to misalignment and a worn UJ.
                        Any comments most welcome. Thanks a head.
                        
                        regards Flemming
                        

                        • "strap Type Propshaft" 

                          Posted By : Steve Cureton, 09-Jul-2006, 11:23am

                          Hi Flemming, I've not got much experience of misaligned propshafts etc but I do know if you slacken off the engine and gerbox montings it will take quite a bit of levering to move things around, so your 'three footer' might be the way to go. If that doesn't fix it though you really do need to find out why it's all misaligned. Are you engine and gearbox mountings in good condition? They're not expensive if you can do the job yourself so I'd consider changing them anyway. If you've got access to an engine hoist I'd seriously consider lifting the whole unit to give you full access to all the mounting points to make sure nothing is bent, don't forget the mounting points on the block are only a metal plate, albeit pretty thick metal, and could be bent. You will also need to cjheck there's no obvious damge to the chassis through accident or rot. Also don't forget to check the diff is mounted correctly and that the surrounding chasis is in good condition, rot in this area is common on our Triumphs, although I suspect if there was any damage you would be very aware of all sorts of handling and noise problems. Finally, I wouldn't rely on secondhand UJs, particulalarly when they haven't been used for 20 years. UJs are not expensive, although they are a bit of a pain to change, but again if you can do it yourself they shouldn't set you back too much.
                          
                          Good luck

                        • "strap Type Propshaft" 

                          Posted By : Chris Taylor, 09-Jul-2006, 11:30am

                          The u/j's in the propshaft are there for the very purpose of dealing with any misalignment, so the position of your engine or gearbox IS NOT AN ISSUE. (My previous comments about easing the engine forward were all about getting the space needed to remove the propshaft and make sure there was not excessive end-thrust on the gearbox and diff). If you think about it, the very same u/j type accommodates HUGE amounts of mislaignment in the swing axles.
                          There should be NO play in a UJ. It can be hard to tell whether there is play there or if it is just the normal backlash in the gearbox and diff when the propshaft is in the car, so it is best removed (again!) and tested on the bench.
                          Although unlikely, I did have a propshaft u/j fail after my car had been off the road for a couple of years being rebuilt, and I attributed this to the grease having dried out, so you might have been unlucky in that way. It is also possible that a previous owner had left a defective u/j for too long and the hole in the flange for the u/j yoke has worn slightly oval. The "cups" of the u/j should be a tight press fit in the flange and shaft "holes." In that case, the only solution is another flange (should be the same as one on the driveshafts for a Herald).
                          

                          • "strap Type Propshaft" 

                            Posted By : Flemming Jensen, 09-Jul-2006, 02:24pm

                            hi Chris and Steve
                            
                            Chris writes:
                            
                            "...There should be NO play in a UJ. It can be hard to tell whether there is play there or if it is just the normal backlash in the gearbox and diff when the propshaft is in the car, so it is best removed (again!) and tested on the bench...."
                            
                            the test was in a bench and it was possible to feel a minor play in one of the UJ's. So, is it reasonably to assume that the noise issue lies there ?
                            

                            • "strap Type Propshaft" 

                              Posted By : Chris Taylor, 09-Jul-2006, 04:57pm

                              No guarantees that this IS the cause of your noise, but I can say there should be NO play in a UJ. Badly worn U/Js usually show up as vibration (over 40mph usually) rather than noise and should be replaced as soon as possible, if only to avoid damaging the flange or driveshaft yokes so the U/J cups can move around instead of being a press fit.

                              • "strap Type Propshaft" 

                                Posted By : Flemming Jensen, 11-Apr-2007, 09:18pm

                                hi
                                
                                I have tried two different strapped propshafts. As discussed in this thread. I am a bit frustrated to say the least. I haven't give up on focusing on the propshaft though. This leads to a new question:
                                
                                Is it possible/advisable to convert a strap drive propshaft to a solid one by simply removing the straps and refit the parts without the straps ?
                                
                                best regards Flemming

                                • "strap Type Propshaft" 

                                  Posted By : Charles Bushell, 11-Apr-2007, 09:55pm

                                  The straps transmit the power while allowing a little longitudinal movement, so no you can't remove the straps or it won't work. There are no splines in the centre.
                                  Charlie

                                • "strap Type Propshaft" 

                                  Posted By : Chris Taylor, 11-Apr-2007, 11:46pm

                                  Not recommended! You can theoretically remove the straps and put a bolt through the two parts of the shaft. HOWEVER, not only is it pretty certain the shaft will then be out of balance, but you will also find the two u/j's are no longer phased apart as they should be, as you will have to turn the rear of the shaft through 90 degrees to fit the bolt between the front and rear sections of the shaft. A solid or splined shaft (preferably roller type) is preferable if you can't sort the strap drive.

                                  • "strap Type Propshaft" 

                                    Posted By : Aaron Tucker, 13-Apr-2007, 12:15pm

                                    hi guys,
                                    
                                    i the previous owener had the straps removed on my car before I got the prop rebalanced, it vibrated badly!! . The rebalancing place would not touch it until I reinstated them, as he said it would be way out of balance and also the nylocks used were too short so it was potentially dangerous!
                                    
                                    I reinstated the straps and had it rebalanced and it works lovely, a friend had suggested i find a prop without the strap drive.
                                    
                                    Aaron

                                    • "strap Type Propshaft", gearbox tie rod 

                                      Posted By : Flemming Jensen, 23-Apr-2007, 12:59pm

                                      hi
                                      
                                      a sub issue: about the "gearbox tie rod" mentioned by Chris Taylor. Does a certain prop.shaft type take a gearbox tie rod compared to another. E.g. will a solid type propshat fit to my strap type propshaft Herald with no gearbox tie rod installed ?
                                      
                                      best regards Flemming

                                  • "strap Type Propshaft" 

                                    Posted By : Flemming Jensen, 20-Jul-2007, 03:33pm

                                    hi
                                    
                                    I have included a picture of the strapped part of the propshaft. Notice the bended staps.
                                    
                                    Do you think the bended straps will cause the prop to make a clonking noise ?
                                    
                                    regards Flemming

                                     

                                    
                                    
                                    "strap Type Propshaft"

                                     

                                    • "strap Type Propshaft" 

                                      Posted By : Ian Mulford, 20-Jul-2007, 03:48pm

                                      You sure the noise isn't the end of the straps hitting the handbrake cable splitter thingy (technical term I know). Normally happens on acceleration as the back of the car squats down.

                                    • "strap Type Propshaft" 

                                      Posted By : Charles Bushell, 20-Jul-2007, 03:52pm

                                      No, they're supposed to bend slightly, that's what takes up the slight longitudinal movement.
                                      If it's clonking one of the ujs is probably worn.

                                      • "strap Type Propshaft" 

                                        Posted By : Aaron Tucker, 20-Jul-2007, 04:34pm

                                        yes i agree with charles they are meant to look like that slightly flexed
                                        
                                        
                                        
                                        see attached pic
                                        
                                        aaron

                                      • "strap Type Propshaft" 

                                        Posted By : Flemming Jensen, 20-Jul-2007, 06:28pm

                                        hi all
                                        
                                        thanks a lot for usefull input. I will continue from here. By checking the "handbrake" possibility and depending on the result replace both the UJ's.
                                        
                                        
                                        regards Flemming
                                        
                                        
                                        
                                        
                                        PS: beside the noise issue the Estate delivers sheer drivers delight. Attached picture from at trip round Danish Countrysite.

                                         

                                        
                                        
                                        "strap Type Propshaft"

                                         

                                    • "strap Type Propshaft" 

                                      Posted By : Chris Taylor, 20-Jul-2007, 11:52pm

                                      Provided there are no broken straps, there is no play between the straps and the bolts, and that the bolts are done up tight, the straps should not cause any clonking noises. IF it is the propshaft causing the problem, then worn U/Js are far more likely.