| Author | Message | |||
     Cliff Biggs Experienced User Username: cliffy Post Number: 62 Registered: 09-2021 |
Have perused the forum for naught and can't find any leads as to where to buy replacement Bosch relays Even non Bosch relays would be OK All I've found are real cheap Amazon specials for about $3 each with plugs no less. They seem to be lager than the metal can Bosch ones but are similar in function What does everyone use when they want to replace relays? | |||
| michael vass Frequent User Username: mikebentleyturbo2 Post Number: 762 Registered: 07-2015 |
eBay | |||
| David Gore Moderator Username: david_gore Post Number: 4117 Registered: 04-2003 |
Cliff, Here is a list of the currently available Bosch relays: https://www.boschautoparts.com/g/relays You will need to contact Bosch International to find your nearest USA Bosch stockist: https://www.bosch.com/contact/  | |||
| Darryl Watson Experienced User Username: inox Post Number: 183 Registered: 04-2015 |
I use common readily available relays designed for automotive use. Make sure that any you buy have a diode across the coil to stop back EMF damaging electronics. The pin configuration is in the manual. Darryl | |||
| Mark Aldridge Frequent User Username: mark_aldridge Post Number: 817 Registered: 10-2008 |
Like Darryl and Mike, I use generic relays with diodes , sourced from ebay, or an online electronics supplier eg RS components or Switch electronics in the UK. No doubt there are similar suppliers in the USA. | |||
| Brian Vogel Grand Master Username: guyslp Post Number: 3311 Registered: 06-2009 |
I have been using what Richard Treacy used to term "supermarket relays," which is what Mark, Darryl, and Mike are using, too. The following may prove helpful. If you get a Bosch-style relay with a diode it should be associated with terminals 85 and 86 which also makes those terminals "unidirectional."  | |||
| Cliff Biggs Experienced User Username: cliffy Post Number: 63 Registered: 09-2021 |
Thanks Looking on line tonight | |||
| Mark Aldridge Frequent User Username: mark_aldridge Post Number: 818 Registered: 10-2008 |
Brian's relay comparison is useful and the late type relays do not suffer from corrosion around the rivets ( a problem I have had on my Shadow and S1). A resistor ( from memory about 600 ohm) or diode can be fitted in the relay base socket to overcome absent diodes between terminals 85 and 86. | |||
| Brian Vogel Grand Master Username: guyslp Post Number: 3312 Registered: 06-2009 |
Mark, But is such a modification even warranted for cars of the era where the Lucas 6RA was used? We just don't have stuff that can be disturbed in the same way as more modern cars do. If I'm buying new relays, I look for ones with diodes fitted these days, but I've replaced Lucas relays with other Lucas relays and, later, third party relays that do not have diodes on my SY series cars without any issue. Brian, who also fitted a diode when I rebuilt my dual SU fuel pump rather than using the resistor supplied. | |||
| Mark Aldridge Frequent User Username: mark_aldridge Post Number: 819 Registered: 10-2008 |
Brian, I generally don't bother, but on my S1 I have an electronic fan controller, electronic ignition and a modern radio cd concealed ( hence conversion to an alternator). Probably totally unnecessary. Also using your conversion I have replaced a number of the hidden relays on the S1 with modern relays. The repro Lucas relays are £30+ each and a poor copy. I like the originals where they can be seen. On a similar note, do not replace blade fuses with cheap spares. I have had a headlight fuse on my S1 which has upgraded fused relay headlight dipping, melt the fuse plastic whilst no fault and running 50% capacity. The fuse did not blow . I have heard of similar problems. All fuses now replaced with premium fuses( eg Littlefuse). Worth checking fuseboard on later SZ series. | |||
| Cliff Biggs Experienced User Username: cliffy Post Number: 64 Registered: 09-2021 |
Mark Interesting point on the fuses I'll be looking for Llittlefuse replacements now | |||
| Cliff Biggs Experienced User Username: cliffy Post Number: 68 Registered: 09-2021 |
Just a question- Did the SZs all come with internal diodes or resistors on the Bosch relays from the factory ? Or is this a modern adaptation for better longevity? | |||
| Mark Aldridge Frequent User Username: mark_aldridge Post Number: 822 Registered: 10-2008 |
Cliff, all post 20000 series cars in the UK, but injection arrived earlier in the USA, so may be earlier in the export series cars . I would be tempted to Replace as original. Mark | |||
| Darryl Watson Experienced User Username: inox Post Number: 188 Registered: 04-2015 |
I think the link below will explain the purpose of the diode across a coil. As apprentices we would give people shocks using a coil and a battery. It's been over half a century since I learned about such things. Regards, | |||
| Cliff Biggs Experienced User Username: cliffy Post Number: 69 Registered: 09-2021 |
Thanks guys I really do appreciate the thoughts but I do understand the purpose of the diodes and also how they work (55 years as an aircraft mechanic) but I was just wondering if the SZ cars used diodes when they first came out without some of the electronics later ones had. Not much electronics until the fan speed module or K lamda injection and the electronic ignition module. Of course later SZs (92-3?) had all the smaller electronic pieces for seats and windows, etc. I can see how on the later SZs that they might have been necessary but again did they have diodes on the relays in the earlier SZs (up to about 89-90)? I can't find any reference for them anywhere I've looked. | |||
| Mark Aldridge Frequent User Username: mark_aldridge Post Number: 823 Registered: 10-2008 |
Cliff, my 1988 and 1990 Model year SZs both have diode relays. Mark | |||
| David Gore Moderator Username: david_gore Post Number: 4119 Registered: 04-2003 |
Here is the article mentioned by Daryl above - I have removed the link from his post to allow this thread to be viewed without scrolling:
| |||
| Cliff Biggs Experienced User Username: cliffy Post Number: 71 Registered: 09-2021 |
Interesting and informative article that I will file away |
PDF