pedlar17 Posted October 26, 2014 Report Share Posted October 26, 2014 Recently stripped the front brakes and suspension for refurbishment, new bushes etc. However the front disc on both sides has a groove worn in the middle of the disc on the rear face. The pad also has raised section mirroring the grove. It is about 0.5mm deep by 6mm wide. Does anyone know what could have caused this? Many thanks Quote Link to post Share on other sites
Motorsport Mickey Posted October 26, 2014 Report Share Posted October 26, 2014 If it was one side it may be possible for a trapped small piece of stone or grit to have grooved it, both sides of the disc in about the same area I'd say it's likely there's a fault in the make up of the disc material causing a softer area and excess wear. Mick Richards Quote Link to post Share on other sites
pedlar17 Posted October 26, 2014 Author Report Share Posted October 26, 2014 It is strange, it is the rear face of both front discs. They are both grooved in approximately the same position, Quote Link to post Share on other sites
RogerH Posted October 26, 2014 Report Share Posted October 26, 2014 Have a look at the structure for a shiny/flattened part or corner. Something structural must be touching the disc. Roger Quote Link to post Share on other sites
John390 Posted October 26, 2014 Report Share Posted October 26, 2014 (edited) I thought that groove occurred when the steering stop cam was not adjusted properly or is missing. This means that the full lock goes too far and the disc catches part of the front suspension. It happened on my wife's TR6 before I adjusted it. Cheers John Edited October 26, 2014 by John390 Quote Link to post Share on other sites
BlueTR3A-5EKT Posted October 26, 2014 Report Share Posted October 26, 2014 (edited) Lock stops missing? I do not think TR 6 has adjustable lock stops like the eccentric things fitted on TR 2/3. Cheers Peter W PS. Or very worn trunnions and bushes perhaps. Edited October 26, 2014 by BlueTR3A-5EKT Quote Link to post Share on other sites
John390 Posted October 26, 2014 Report Share Posted October 26, 2014 They did on my wife's 69 TR6! Cheers John Quote Link to post Share on other sites
BlueTR3A-5EKT Posted October 26, 2014 Report Share Posted October 26, 2014 I stand corrected. Quote Link to post Share on other sites
Guest ntc Posted October 26, 2014 Report Share Posted October 26, 2014 Callipers not shimmed correctly. Quote Link to post Share on other sites
pedlar17 Posted October 26, 2014 Author Report Share Posted October 26, 2014 I have checked all mechanical parts but cannot find any worn part. The stop does not seem to be adjustable. I wish I had found this before disassembly, as I may have found the culprit. Quote Link to post Share on other sites
John390 Posted October 26, 2014 Report Share Posted October 26, 2014 The stop is as Peter described. It is a circular section of metal that is held with one bolt. The hole is off centre so as you turn it you can adjust how close the disc can get to the suspension. Cheers John Quote Link to post Share on other sites
Guest ntc Posted October 26, 2014 Report Share Posted October 26, 2014 You would see wear marks on the suspension components. When you stripped it did you shim it up?. Quote Link to post Share on other sites
jamesStag Posted October 26, 2014 Report Share Posted October 26, 2014 Hi, I have exactly the same marks as Pedlar17. I also read that the end stops were not correctly adjusted. So put my car up on 4 pillar hoist and moved steering lock to lock and inspected. Could not see anything that looked adjustable as a stop, but did see that one of the trunnion lower link split pins was rather close at end of lock. So re-shaped/moved the end of the pin. If anyone could please clarify what these end stops look like that would be handy. Thanks and cheers, J.. Quote Link to post Share on other sites
RogerH Posted October 27, 2014 Report Share Posted October 27, 2014 Hi James, as stated by John, they are a small disc of steel apprx 5/8"diameter and 1/4" thick. They are bolted to the TRunnion with a 1/4"unf bolt. As the TRunnion rotates the disc will hit a stop on the TRunnion and that gives the limit of full movement http://www.moss-europe.co.uk/Shop/ViewProducts.aspx?PlateIndexID=2789#78 item 78. Roger Quote Link to post Share on other sites
Peter Cobbold Posted October 27, 2014 Report Share Posted October 27, 2014 Posts 16 onwards here covers the lack of lockstop causing grooving: http://www.tr-register.co.uk/forums/index.php?/topic/49030-anti-roll-bar-poly-bushes/ photo on post 22 shows where lockstop should be screwed in. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted October 27, 2014 Report Share Posted October 27, 2014 (edited) Q: Does the lock stop on your car actually hit up against the tab on the base of the V post when the trunnion is rotated L to R? If not a taller lock stop might be required - the early car lock stop was half the height of the 15611 TR6 item. Perhaps a pile of washers of a larger diameter than the existing lock stop could be substituted. Parts History Time for us Anoraks 142403 was the eccentrically drilled lock stop spacer tube fitted TR4A-5-250 & TR6 (as fitted on 1969 models only pre CC/CP50000 - no comm number change point given) This was adjustable to give max steering lock without impingement of parts. 156111 was the concentrically drilled lock stop spacer tube fitted TR6 - no engineering change point is given but 1970 build or CC/CP50001 onwards could be a reasonable guess. This was not adjustable so the max steering lock is fixed. Cheers Peter W PS Just a thought - which way up are your lower wishbones fitted - the eye should droop down both ends when fitted. Is this a possible cause? They can be fitted both ways - if the inner stud is removed and the hole is through threaded. No flat machined on the upper face inner stud hole though. Lowering trick from all accounts. Edited October 27, 2014 by BlueTR3A-5EKT Quote Link to post Share on other sites
dingle Posted October 27, 2014 Report Share Posted October 27, 2014 I had the same problem-mysterious groove on the rotor. The trunnion bolt head or nut was contacting the rotor on full lock. I made a steering stop collar sligtly larger to prevent contact as the existing collars were drilled concentrically. Grinding or machining the bolthead or nut would have been another solution. Be sure to check full lock in both directions on both wheels. Berry Quote Link to post Share on other sites
BlueTR3A-5EKT Posted October 27, 2014 Report Share Posted October 27, 2014 Aha! What about the top ball joint bolts. Outer one should have the head at the rear. Quote Link to post Share on other sites
Mark69 Posted October 27, 2014 Report Share Posted October 27, 2014 Top ball joint sits higher than brake disc and bolts to the rear of vertical shaft. What ever is rubbing on disc as to get past the rear disc guard Mark. Quote Link to post Share on other sites
Guest ntc Posted October 27, 2014 Report Share Posted October 27, 2014 Top ball joint sits higher than brake disc and bolts to the rear of vertical shaft. What ever is rubbing on disc as to get past the rear disc guard Mark. Quote Link to post Share on other sites
Mark69 Posted October 27, 2014 Report Share Posted October 27, 2014 Hi Changed the faulty boot on my top ball joint this evening , took a pic with the wheel removed. Hope it helps to put all these replys in order. Mark Quote Link to post Share on other sites
Guest ntc Posted October 27, 2014 Report Share Posted October 27, 2014 Mark I am going to the dentist Quote Link to post Share on other sites
stuart Posted October 28, 2014 Report Share Posted October 28, 2014 I had the same problem-mysterious groove on the rotor. The trunnion bolt head or nut was contacting the rotor on full lock. I made a steering stop collar sligtly larger to prevent contact as the existing collars were drilled concentrically. Grinding or machining the bolthead or nut would have been another solution. Be sure to check full lock in both directions on both wheels. Berry That is very often where the problem arises. I have come across instances where even with eccentric stops fitted the trunnion bolt will still touch and it can be down to moving the split pin and nut round a little. Stuart. Quote Link to post Share on other sites
peejay4A Posted October 28, 2014 Report Share Posted October 28, 2014 (edited) They even put a neat hole in the dust cover/stone guard to allow the bolt head to make contact with the disk Edited October 28, 2014 by peejay4A Quote Link to post Share on other sites
pedlar17 Posted October 29, 2014 Author Report Share Posted October 29, 2014 I think you might be right. It may be the bolt head.As all bolts were pretty knackered. The stop plate on my car is concentric there is no adjustement it is an early uk 72 . When I reassemble I will check the bolt heads. Thanks everone. Quote Link to post Share on other sites
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