Oilite or Lead-bronze bushes on Girdraulic, timing and RFM?

Trinorvin

Forum User
VOC Member
Hello everybody,
as I wrote in the title, it is time for me to renew these parts on my Comet. Different prices and quality of bushes are supplied by many Vincent stockists. It appears that the best choice would be Lead-bronze bushes? Have you any experience and comments on the subject considering that all bushes are seized on spindles and turn in the links! (Steel spindles and Lead-bronze bushes). Fortunately, without too much play and not perceptible ovality.
Does Loctite or grease nipples trapping the bushes are a good miracle cure? Obviously, the spindles will be replaced by stainless steel ones.
Does bushes G90, FT117 on RFM, Et64 between UFM and RFM ask Oilite material due to difficuty to be reached with grease through treaded nipples? Or care on Lead-bronze bushes with frequent oiling in lateral clearance is sufficient?
I guess to extract the camshaft, camfollower and small idler spindles with a puller extractor after heating the case around. Does it is a too load tool or I can do the job with a plier?
I have several questions and other will come...
Thanks in advance from France
Trinorvin
 

clevtrev

Well Known and Active Forum User
VOC Member
Hello everybody,
as I wrote in the title, it is time for me to renew these parts on my Comet. Different prices and quality of bushes are supplied by many Vincent stockists. It appears that the best choice would be Lead-bronze bushes? Have you any experience and comments on the subject considering that all bushes are seized on spindles and turn in the links! (Steel spindles and Lead-bronze bushes). Fortunately, without too much play and not perceptible ovality.
Does Loctite or grease nipples trapping the bushes are a good miracle cure? Obviously, the spindles will be replaced by stainless steel ones.
Does bushes G90, FT117 on RFM, Et64 between UFM and RFM ask Oilite material due to difficuty to be reached with grease through treaded nipples? Or care on Lead-bronze bushes with frequent oiling in lateral clearance is sufficient?
I guess to extract the camshaft, camfollower and small idler spindles with a puller extractor after heating the case around. Does it is a too load tool or I can do the job with a plier?
I have several questions and other will come...
Thanks in advance from France
Trinorvin
9 times out of 10, the spindles will drop out before you have finished heating !
I use aluminium bronze for rotating bushes. Loaded nylon with high tensile stainless for the girdraulics and eccentrics.
 

Martyn Goodwin

Well Known and Active Forum User
Non-VOC Member
I HAD loaded nylon bushes in my Girdraulics but found that oil based lubricant caused then to swell then seize solid. I replaced them with BRONZE bushes that I got from Covenrty in the USA - I beileve these are exactly the same as those available thru the spares company............... Sorry Trev - but it is (just) my experience that the nylon stuff is rubbish.

As to movement within the girdraulics- I have set mine up with the bushes both turning on the spindles AND within the links - this is an area where you want freedom of movement without binding but at the same time, no lateral free play.

Also, talking about bushes - There are also bushes in the pivot points where the seat stays attach to the underside of the seat at the rear and there is another pivot point where the front of the seat attaches to the UFM. If ANY of these pivot points are binding then that additional and unwanted friction will have a detrimental impact on the overall performance of the rear suspension.

While the sintered bronze bearings in the seat stay end (FT111) are readily accessible and visible and thus most likely receive appropriate maintenance to keep them free, the bearing at the front of the seat is a different story. The front of the seat is positioned on a 3/8” seat pivot rod (F35/1) that passes thru a steel tube (F57/1) which itself passes thru the top hole at the rear of the UFM. There are two sintered bronze bushes (ET64), one each side, between the bore of the UFM hole and the thru tube. The intent is that the overall length of F57/1 is slightly greater than the length of the hole thru the UFM. What this means is that once the front seat bolts on F35/1 are tightened the seat frame is held securely (and unmoving) against the ends of the tube F57/1. However, because of the two sintered bronze bushes, the tube itself can readily rotate within the UFM and in turn the seat can also freely move in the vertical plane as required. Well that’s the theory! In my case I found that both ET64's were seized solid resulting in a seat that was very difficult to pivot.

The fix was a new F35/1, new ET64's (actually I sourced suitable oilite bushes from a local bearing supplier) and a home made replacement for F57/1 from suitable SS tube, so that I could be sure of the required fit and free movement. The hole in the UFM (for the ET64's was cleaned up using a sanding drum on my Dremel tool.

Martyn
 

BigEd

Well Known and Active Forum User
VOC Member
VOC Forum Moderator
I may have misinterpreted what you have said here but this does not sound like good engineering practice.
............
As to movement within the Girdraulics - I have set mine up with the bushes both turning on the spindles AND within the links - this is an area where you want freedom of movement without binding but at the same time, no lateral free play.

Martyn
 

chankly bore

Well Known and Active Forum User
Non-VOC Member
Sorry, Martyn, but I agree! The bushes should never turn in their eyes. You're giving the component a place to wear where wear wosn't!
 

Martyn Goodwin

Well Known and Active Forum User
Non-VOC Member
What I have done is ensure that the shafts rotate freely within the bushes and in turn that the bushes themselves are a snug fit in the housings though I have NOT used any mechanical or chemical means to LOCK the bushes in the housings

Martyn
 

BigEd

Well Known and Active Forum User
VOC Member
VOC Forum Moderator
Dear Martyn,
That sounds much better.:)

What I have done is ensure that the shafts rotate freely within the bushes and in turn that the bushes themselves are a snug fit in the housings though I have NOT used any mechanical or chemical means to LOCK the bushes in the housings

Martyn
 

stumpy lord

Well Known and Active Forum User
Non-VOC Member
I HAD loaded nylon bushes in my Girdraulics but found that oil based lubricant caused then to swell then seize solid. I replaced them with BRONZE bushes that I got from Covenrty in the USA - I beileve these are exactly the same as those available thru the spares company............... Sorry Trev - but it is (just) my experience that the nylon stuff is rubbish. I have know idea of what grade of nylon that you used, and yes I agree that some of the earlier nylons used for bushes where a complete waste of time. what I do know is that the impregnated nylon bushes suplied by Trevor are the bees knees, my son Roger and I have been using them now for many years without any problems, all we have to do is give them a dose of moly grease once a year, and fore get about them So it would seem one has to be care full from where you get your bushes from.
cheers stumpy lord.

As to movement within the girdraulics- I have set mine up with the bushes both turning on the spindles AND within the links - this is an area where you want freedom of movement without binding but at the same time, no lateral free play.

Also, talking about bushes - There are also bushes in the pivot points where the seat stays attach to the underside of the seat at the rear and there is another pivot point where the front of the seat attaches to the UFM. If ANY of these pivot points are binding then that additional and unwanted friction will have a detrimental impact on the overall performance of the rear suspension.

While the sintered bronze bearings in the seat stay end (FT111) are readily accessible and visible and thus most likely receive appropriate maintenance to keep them free, the bearing at the front of the seat is a different story. The front of the seat is positioned on a 3/8” seat pivot rod (F35/1) that passes thru a steel tube (F57/1) which itself passes thru the top hole at the rear of the UFM. There are two sintered bronze bushes (ET64), one each side, between the bore of the UFM hole and the thru tube. The intent is that the overall length of F57/1 is slightly greater than the length of the hole thru the UFM. What this means is that once the front seat bolts on F35/1 are tightened the seat frame is held securely (and unmoving) against the ends of the tube F57/1. However, because of the two sintered bronze bushes, the tube itself can readily rotate within the UFM and in turn the seat can also freely move in the vertical plane as required. Well that’s the theory! In my case I found that both ET64's were seized solid resulting in a seat that was very difficult to pivot.

The fix was a new F35/1, new ET64's (actually I sourced suitable oilite bushes from a local bearing supplier) and a home made replacement for F57/1 from suitable SS tube, so that I could be sure of the required fit and free movement. The hole in the UFM (for the ET64's was cleaned up using a sanding drum on my Dremel tool.

Martyn

I have know idea of what grade of nylon that you used, and yes I agree that some of the earlier nylons used for bushes where a complete waste of time. what I do know is that the impregnated nylon bushes suplied by Trevor are the bees knees, my son Roger and I have been using them now for many years without any problems, all we have to do is give them a dose of moly grease once a year, and fore get about them So it would seem one has to be care full from where you get your bushes from.
cheers stumpy lord.
 

clevtrev

Well Known and Active Forum User
VOC Member
Surely the supplier of your nylon bushes, would have warned you of the possibility of the expansion problem, and told you to set them up initially with the required three thou clearance. So that after the expansion has taken place, all would be seen to be satisfactory.
I know of a bike that has over 100,000 miles on it, and the bushes and movement are still perfect, with no wear at all.
 

VincenttwinPL1

Forum User
Non-VOC Member
100000 miles and no wear to the bushes or spindles, thats very impressive. How is the nylon lubricated? Are there grease grooves in the bushes?
 
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