If the WAN ports on both routers are used, that's a problem. Any reason you didn't configure the second router as a WAP?
I have got two Linksys EA650 routers. One of them is connected to the main one via Ethernet cable in bridge mode.
The bridged one has two external HDs connected.
My problem is that the USB hard drives are not visible by none of computers connected wirelessly to the network.
I will deeply appreciate any helpful suggestion.