Cat mounting bolts
 

Hi All,

The cat in my 1999 Honda Accord is fixed to the front neighbour part of exhaust system using 3 bolts 18176-PT0-003 and to the rear neighbour part using 3 bolts 18176-P08-003. Wherever I look them up they're priced starting from $8. Are they some special bolts and no other ones will fit or won't come off if installed instead of them? The matching nuts are priced at just $0.30 each.

Many thanks,
Dmitriy

Saloon or Coupe?
The 4-door car is different from our USA Accord, so the exhaust might be different too.

First, those bolts get pretty hot, so it's a concern about the high-temperature strength. Still, if you are comfortable replacing them periodically, you can buy a lot of 304-stainless bolts from the hardware store.

Honda has "traditionally" used donut gaskets with spherical seats so the exhaust can flex at that joint (aft end of the cat). Those bolts have an arrangement of a spring along with an extended shoulder bolt. You'll have to make up a strange arrangement of a long bolt, double-nutted, to properly hold the spring.

Thank you for the reply. It's a Saloon, model CG9, VIN = SHHCG9540XU006596, made here in Swindon:
HONDA ACCORD VII 2.0i VTEC CG9 F20B6 AUG-98 TO MAR-03 (6th Gen)

(btw I keep asking myself what VII means if that's 6th generation!)

> Still, if you are comfortable replacing them periodically, you can buy a lot of 304-stainless bolts from the hardware store.

That's exactly what I'd like to do as the ones currently there are so heavily rusted and burnt that the garage said they'd just cut them off; I also cannot see too much value in so HQ and expensive bolts if there's no chance to unscrew them after a while. So my preference would be 304 SS (perhaps marine A4 grade) bolts as long as they can join the parts together reliably.

> Those bolts have an arrangement of a spring along with an extended shoulder bolt.

Makes sense - so they're kind of unique then. I'll take a look at that joint: hopefully it's straight, in which case I guess I could replace them with straight ones and that won't be critical... meanwhile just wondering if garages tend to install special ones when doing cat or exhaust replacements.

Yes, that would be the 6th-generation of the Accord. Roman-number 7... uh huh...

If those bolts have a spring at each bolt, then just make up something that also incorporates the spring. The system NEEDS to flex as the engine moves.

Thank you - actually I've just realised I may not need to touch that joint at all: I'm preparing to take off just the front down exhaust pipe in order to swap the oil pan. Still it was very useful to learn about these flexible joints as sooner or later I'll have to replace either the cat itself or the exhaust part attached to its aft.